Wikipedia talk:Manual of Style/Dates and numbers

It has been 2997 days since the outbreak
of the latest dispute over date formats.

Area conversions

I started a thread over at Template talk:Convert#Area, but was advised to also raise it here for advice. Is there any good reason to move away from the default values for area conversions, e.g. by converting acres into square kilometres, or hectares into square miles, etc? Thanks. Martinevans123 (talk) 12:39, 5 April 2016 (UTC)

I would prefer to see hectares, square miles and acres all converted to square kilometres (or square metres). That way I would be able to understand any one of them. Dondervogel 2 (talk) 21:20, 7 April 2016 (UTC)

Thanks for sharing. Is there no policy here? Is the acre still seen as the "primary unit" for land area in both US and UK? Martinevans123 (talk) 21:36, 7 April 2016 (UTC)

I prefer default conversion to the closest size unit, to avoid unnecessary (insignificant) zeros adjacent to the decimal point, as in "13 acres (0.053 km²)" or "98 square kilometres (24,000 acres)".

WP:UNIT isn't clear on which is to be considered the primary unit for land area in the UK. I'd just go with whatever system the article was using. There are often good reasons for choosing a different unit from the {{convert}} default whether it's area or some other dimension. For example, you might have a number of national parks mentioned in a paragraph, some large and others small, some may may be measured in hectares but I wouldn't convert to acres if most of the other parks are over 3 square kilometres (then again, it might be better in this case to use square kilometres for all the parks). The {{convert}} default was never intended to be a preferred unit to convert to but a guess at what might be the most commonly desired and/or useful one. Jimp 08:33, 8 April 2016 (UTC)

Yes, a guess. But what do you think about cross converting from units to square units and vice versa? It seems unjustified to me. Thanks. Martinevans123 (talk) 08:52, 8 April 2016 (UTC)

Caught in an edit conflict, I was adding "Another example might be a paragraph about a number of farms most of which are between 5 and 2,500 acres but there are a couple which are in the ten and hundreds of thousands of acres, you'd probably want to convert the big ones to square kilometres even though you might be using hectares for the smaller ones.". I'm not sure what you mean by cross-converting from units to square units. Square units are units. If you mean converting feet to square metres, obviously you can't do that, but if you mean acres to square kilometres, there's nothing wrong with that (they're both area, just as you might convert litres of engine displacement to cubic inches or foot-pounds to joules). Perhaps you meant something different. Jimp 09:06, 8 April 2016 (UTC)

The default for acres is hectares, and vice versa. The default for mi2 is km2. By cross converting I mean acres to km2 etc. {"Acres" and "hectares" don't have the word "square" in them). But I understand your example which looks perfectly fair, although using a mixture of units in the same article is a slightly different case to mine. Martinevans123 (talk) 09:22, 8 April 2016 (UTC)

The sudden appearance of a unit name is unusual but not unexceptional in the metric system. The most common example is the tonne, which is used instead of the megagramme. Hawkeye7 (talk) 22:57, 29 April 2016 (UTC)

The reason for defaults such as km² ←→ sq mi, acre ←→ ha, m² ←→ sq ft, etc. is that these are close in size and/or used for similar purposes; it had nothing to do with keeping square length units separate from straight area units (e.g. the default for square hectometres is acres). There's no problem with the cross-conversion you describe just as you could convert knots to/from kilometres per hour or calories per minute to/from watts. Just as long as you've got the right dimension (i.e. length to length, area to area, speed to speed, etc.), I'd say the conversion would be fine. Jimp 03:59, 13 April 2016 (UTC)

I think I was just assuming that the primary reason for putting in an area conversion, in say a geo article for a town or village, would be to show Imperial and metric equivalence. I was searching for a guideline which gives clear advice on when km² would be preferable to the default of 'ha, from acres. Perhaps something along the lines of "choose the units that produce a result with the fewest number of zeros", etc. But I don't see one. Thanks. Martinevans123 (talk) 21:48, 17 April 2016 (UTC)

I still think conversion from hectare to square metres (or square km) is needed. Acre means nothing to me except as one hundredth of the size of the wood from Christopher's childhood days. Dondervogel 2 (talk) 12:02, 17 April 2016 (UTC)

Not even the ones sacred to the Moravian Church? [1]. Martinevans123 (talk) 17:32, 17 April 2016 (UTC)

Well ... I confess I'd heard of the Waco massacre, but I'm not familiar with the conversion to kilograms. Dondervogel 2 (talk) 21:13, 17 April 2016 (UTC)

I think David was trying to convert 7 days into something a bit more permanent. Martinevans123 (talk) 21:31, 17 April 2016 (UTC)

The defaults give you the recommended conversions in every case, at least for area. If you would use square miles in imperial, use square kilometres; if you would use acres, use hectares; if you would use squares, use square metres. Square kilometres is never acceptable where acres were formerly used. Hawkeye7 (talk) 23:04, 25 April 2016 (UTC)

I would wholly agree. That's the rule I have tended to always apply. But it's not written down as a policy, is it? Martinevans123 (talk) 22:21, 26 April 2016 (UTC)

No, because Imperial measurements are more context sensitive than their metric counterparts. We could lay down a firm guideline for area though: always use hectares for acres and vice versa. (An acre is a furlong by a chain.) Hawkeye7 (talk) 22:57, 29 April 2016 (UTC)

I've just noticed this last remark here and want to register my dissent: neither acres nor hectares are defined in the SI system, so both should be converted to square kilometres so that mere mortals can understand. Dondervogel 2 (talk) 15:52, 25 May 2016 (UTC)

I have to say that I, personally, have only the foggiest idea of how much an acre is, and no idea at all how much a hectare is. While you're here, can you take a look at the when-not-to-convert thread below? More comment would be welcome. EEng 16:24, 25 May 2016 (UTC)

• Helpful analogy. EEng 01:58, 30 April 2016 (UTC)

The ha is accepted for use with the SI system and just another name for hm². It is the closest such unit to the acre. Nothing wrong with using it for converting from acres. −Woodstone (talk) 17:09, 25 May 2016 (UTC)

Question: use of ordinals in article titles

I've got a question about writing ordinal numbers in article titles. Take, for example, First Salmond government. I can't help but feel like 1st Salmond government might be more concise (if less formal), in some trivial way, but the MoS does not seem to give any guidance on this matter. Has anyone any opinion on whether "first" or "1st" is preferable in such an instance as this? RGloucester — ☎ 02:26, 17 May 2016 (UTC)

• This has all the makings of a really good fight. I've fastened my seatbelt.

While we're waiting for the first blow to be struck, I'd like (as tradition demands, here at DATESANDNUMBERS) to make at least a token effort to derail the conversation before it even starts, by raising an irksome quibble stimulated by the OP's query, but substantively irrelevant to it. In this case, I choose to take issue with the phrasing "but the MOS does not"; I believe it should be simply "but MOS does not". Commence firing!

OK, just kidding. My feeling is that this just looks odd -- probably the same feeling that gave rise to the exhortation (WP:NUMNOTES) to avoid beginning a sentence with a numeral. Think how it would look in a See also section:

See also

• Scottish history
• Highland Games
• 1st Salmond government
• Scottish cuisine

Well... now that I look at it, I don't know... EEng 03:09, 17 May 2016 (UTC)

• I've learned to live with the dictum in most style guides against starting a sentence with a numeral (but I've been known to breach it to avoid the cumbersome, reader-unkind wording that often results). I think people are not yet ready for "1st" in opening position in a title (and maybe even in other positions), unless there's a compelling reason for it. But I could be persuaded, I suppose. Tony (talk) 03:21, 17 May 2016 (UTC)

• Good style (as reflected in the usage of the best writers since the nineteenth century, not to mention a majority of academic style manuals) requires that numbers (cardinal or ordinal) that can be written in one or two words be so written. (Newspaper style, concerned with saving type and column-inches, even today, limits that to numbers under 100, but the outcome is not much different.) Good style also requires that sentences and titles begin with words, not numerals, though many good writers make an exception for big numbers, where starting with a word would be awkward. Even so, Orwell's novel is Nineteen Eighty-Four, not 1984. Conciseness is not the highest goal to which a writer can aspire. J. D. Crutchfield | Talk 03:45, 17 May 2016 (UTC)

I don't want to get into any nonsense about what's "good", but I will say that I'm quite aware of the relevant standard, and would not suggest such usage in prose. In my query above, I am specifically referring to article titles, where conciseness is indeed one of the relevant criteria. I also find the juxtaposition between the capitalised "First" and lowercased "government" to be somewhat jarring, which is perhaps what spurred my question. I feel "1st" to be somewhat more acceptable in a descriptive title than in proper name, but I suppose there isn't much to be done. RGloucester — ☎ 03:52, 17 May 2016 (UTC)

would not suggest such usage in prose So how would you go about linking to this article if not as [[1st Salmond government|(f|F)irst Salmond government]]? Save yourself the grief, IMO--conciseness is not the only article-naming criteria, and the delta is only 2 characters. --Izno (talk) 11:08, 17 May 2016 (UTC)

• Izno's example seems compelling. Using 1st is a bad idea. EEng 11:52, 18 May 2016 (UTC)

Unit conversions in science articles

The MOS states " In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so." What is meant by this? In every FAC or GA about animals (science) I've nominated, I've been asked to add conversions. What is a "special reason? And what is not a "special reason"? Seems extremely ambiguous/arbitrary. FunkMonk (talk) 09:09, 18 May 2016 (UTC)

It means that for most articles, if you report a power measurement as 10 W, you don't need to provide a conversion to BTU/h. Or if you report an asteroid size as 20 km, you don't need to convert to miles. A 'special reason' would be the article is of high general interest, like in the case of Jupiter where its size is given in both km and miles, or if the dimensions of a certain piece of equipment is standard in non-SI unit, like a 2.54 cm (1 in) diameter rod. Headbomb {talk / contribs / physics / books} 09:20, 18 May 2016 (UTC)

But why the exception? Isn't it always relevant to show these conversions (at least dimensions and weight, helpful for any reader), regardless of whether it is a science article or not? Again, seems very arbitrary. FunkMonk (talk) 09:23, 18 May 2016 (UTC)

Because sometimes conversions help. But plastering them all over the place isn't good. In astronomy, for instance, galaxies sizes and distances are measured in parsecs and conversions often given in lightyears. But having "M31 is located 780 kiloparsecs (2.5×10⁶ ly, 2.4×10¹⁹ m, 1.5×10¹⁰ mi) from earth." is fairly pointless, given no one has an intuitive idea of just how big any of those numbers are. These are astronomical distances, and the most we can expect of readers is that some of them will remember that the nearest star is 4 light years away. The km or mile value of that distance adds nothing to the understanding, but this is also why we link the first instance of those non-SI units (someone can always check how big one parsec is in km or mile if they really want to). Headbomb {talk / contribs / physics / books} 09:48, 18 May 2016 (UTC)

In that case, the MOS text is misleading. If the specific problem is only with huge distances, very technical units, etc, that should be the exception ("special reasons"). Science articles as a whole should not be a general exception. We're now in a situation where for example the size of organisms, the weight of small meteors, etc, are somehow exempt from conversion, for no good reason. FunkMonk (talk) 09:56, 18 May 2016 (UTC)

Not really. If you write a "10 μm wide bacteria", you shouldn't convert that to thous. Nor the mass of meteors reported in slugs. Science is done in SI, 90% of the time, and conversions aren't needed except in special cases. Headbomb {talk / contribs / physics / books} 10:09, 18 May 2016 (UTC)

Ok, let's be more specific then. Animal, plant, and anatomy articles, which we have tens of thousands of (a considerable percentage of our science articles, therefore hardly "special cases"). Why are they exempt? If they aren't, we need to state what exactly is considered "special reasons", otherwise we leave too much room for interpretation. Or we could say that some non-technical units, such as metres, kilos, etc, should always be converted. FunkMonk (talk) 10:13, 18 May 2016 (UTC)

FunkMonk, there may very well be room for clarification here. To make the discussion concrete, can you give us two or three specific article passage you're concerned about, explaining how this MOS provision isn't clear with regard to how they should be treated? EEng 11:51, 18 May 2016 (UTC)

This GAN discussion about the dimensions of a fossil egg (bullet point 10, which is what brought me here) gives a pretty specific example of how the ambiguity creates a problem:[2] In this case, the measuerement is so small that it is probably fine. But I have never seen anyone bring that guideline up before in this context, but nothing stops it from happening henceforward and in more general contexts. FunkMonk (talk) 12:01, 18 May 2016 (UTC)

Hmmmm. Where the dimensions of the egg are described it seems useful for the general reader, if he happens to be unmetricated, to get a conversion to inches -- these are big, big eggs and the reader should get an idea of how big. But by the time we get to the thickness of the shell, while that's important for people who work with dinosaur shells, I'm not sure it tells the lay reader much to convert that to thousandths of an inch or whatever.

On the other hand, what does it hurt to do so anyway? I think it hurts nothing, except in a heavily technical article, with many measurements of a kind that laymen won't appreciate anyway, in which case perhaps the constant interruption for conversions becomes tiresome.

So in the example you give, I'd convert everything. If I'm right in what I say above, then the wording should be adjusted. But this just preliminary thinking on my part. Others' thoughts?

EEng 13:10, 18 May 2016 (UTC)

P.S. Changed my mind on my point above that "I'm not sure it tells the lay reader much to convert that to thousandths of an inch or whatever". At the GA review, someone said, "people generally don't have an intuition for how small 0.043 inches is, even if inches come more naturally to them that metric units". That makes me realize how useful such a conversion actually is. I'm sorry to say I'm one of the Great Unwashed and Unmetricated, so that inches do come most naturally to me; but I also have a technical background, so when I see 0.043 inches, I can immediately say, "Hmmm, yes, that's a bit less than 1/20 of an inch", and that's useful to me.

Yeah, my point is that nothing in the guideline makes clear what is considered a "special reason", and that it is so ambiguous and arbitrary as to be useless. In theory, could we deny conversion for the weight of an elephant? The guideline doesn't specify whether that is a "special case" or not. FunkMonk (talk) 13:18, 18 May 2016 (UTC)

Let us hope our esteemed fellow editors contribute a few more actual-article examples as food for thought. From that may come a crystallization of our thinking on possible changes to the guideline's wording. EEng 13:48, 18 May 2016 (UTC)

I don't know the turnover rate of this talk page, but I fear this section will be archived before that happens... FunkMonk (talk) 14:02, 18 May 2016 (UTC)

You'd be surprised. It's a worthy topic. Anyway, the bot's set to leave a minimum # of threads around indefinitely. Be patient. EEng 14:37, 18 May 2016 (UTC)

Picking up on the mention of plant articles above, it's clear that many US readers want customary units for the dimensions of plants, so at least for those plants found in North America, it's common to provide conversions. This seems reasonable to me; whether it should be spelt out in the MoS I'm not sure. Peter coxhead (talk) 17:30, 18 May 2016 (UTC)

While we're on the subject of conversions, is there any progress on converting acres to km^2 instead of (or as well as) to hundredths of Christopher Robin's blessed wood? Dondervogel 2 (talk) 19:25, 18 May 2016 (UTC)

And btw I'd gladly provide an example of whatever it is you are looking for examples of, but I'm not sure what that it is. Is it conversions missing where they are needed, present when not, present when needed, absent when not, or none of the above? Dondervogel 2 (talk) 19:29, 18 May 2016 (UTC)

Surely Wikipedia should use hectares, rather than Km^2, to convert acres? A hectare is just under two and a half acres, whereas a square kilometer is nearly 250. But what do I know? I'm an American, and unschooled in the mysteries of the metric system. (I do know, however, with all due respect, that Christopher Robin's Hundred-Acre Wood does not deal in hundredths.) J. D. Crutchfield | Talk 21:48, 18 May 2016 (UTC)

We always use hectares to convert acres. Square kilometres is used to convert square miles. Hawkeye7 (talk) 23:30, 18 May 2016 (UTC)

I think what we need are examples, drawn from your experience, where what seems to be a good decision about whether to convert or not convert is in tension with the current wording, "In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so". So far, I'm tentatively convinced that, even in "science-related articles", the general description of a plant or animal should usually be converted, so that laymen can envision the organism. EEng 22:26, 18 May 2016 (UTC)

The main purpose of conversion is to maintain faith with the original sources when they are using the old measurements. Everybody should know metric; it's used in nearly every country and even in the United States it is part of the common core. While my father would still measure the height of a horse in hands and its weight in stones, I don't know if that would be worth the effort for the majority of readers. Hawkeye7 (talk) 23:43, 18 May 2016 (UTC)

No, the main purpose of conversion is to ensure that a reasonably large %age of readers have an intuitive understanding of at least of the units in which a measurement is presented. I'm sorry, but while I agree everyone "should" know metric, but the fact is that most in the US don't (your talk of common core notwithstanding -- most US high school students take X years of a foreign language, but that doesn't mean we should present articles in Spanish, French, or German only, expecting them to understand one of them). EEng 00:45, 19 May 2016 (UTC)

The Large Hadron Collider uses {{convert}} extensively (km to miles, metres to feet, Kelvin to centigrade, m/s to mph, Mega Joules to tons of TNT), which all seem to be eminently sensible conversions to include.

The example above concerning parsecs (at Andromeda Galaxy) converts parsecs/light years/astronomical units and metres to inches (telescope size), but doesn't convert 218-ft to metres (size of Transit Telescope) which would be an improvement.

Supercooling consistently converts temperatures in Kelvins to centrigrade and fahrenheit.

Celsius, not centigrade. Hawkeye7 (talk) 23:43, 18 May 2016 (UTC)

There is absolutely nothing wrong with "centigrade" in the English language. I can't imagine what utility was meant by the above comment. RGloucester — ☎ 03:02, 19 May 2016 (UTC)

-- (signed) Disgusted of Tunbridge Wells 07:17, 19 May 2016 (UTC)

"Centigrade" is purely historical. It was renamed "Celsius" in 1948. Hawkeye7 (talk) 08:40, 19 May 2016 (UTC)

It doesn't matter what some trifling international organisation has named anything. People use it, and there is nothing inherently wrong about it. It was renamed for reasons unrelated to its English usage. Meaning is conveyed without ambiguity, and hence there is absolutely no reason to stick up one's hand in such a swashbuckling manner. Please consider others before going on such tirades. RGloucester — ☎ 13:36, 19 May 2016 (UTC)

-- (signed) Disgusted of Tunbridge Wells 02:26, 20 May 2016 (UTC)

Looking around for some biology examples I came across Histology where the sections Processing - dehydration clearing and infiltration and Sectioning use namometres and micrometres without any conversion (or any comparative objects - see 1 micrometre and 100 nanometres for possible comparisons), but does note that 1000 micrometres = 1 mm. The article uses values around 5 micrometres (0.0002 in) - maybe not a particularly useful conversion but I can get a bit of a sense of that - it's one fifth of a thou (thousandth of an inch - the thinnest blade in car mechanic's imperial feeler gauge set).

It does seem to me that the scientific articles that do include appropriate conversions are more understandable than those that do not. Even being more than semi-metricated and semi-washed I find still find it useful to know the thickness of the eggshell mentioned above is about 40 thou - that gives me a very good idea of how thin the eggshell is... Robevans123 (talk) 23:32, 18 May 2016 (UTC)

• Guilty as charged: I was the one who pushed for the optional exclusion of British Empire (i.e. US) units in scientific articles, waaaaaay back a decade ago. Please, doesn't every single American schoolkid have exposure to the international system? The clutter factor can become really intrusive in some science articles. Tony (talk) 07:34, 19 May 2016 (UTC)

I see. But isn't "clutter" (including in-text explanation of terms[3]) a necessary evil to make complex articles understandable for layeaders? And shouldn't exclusion of conversions be the exception rather than the rule? FunkMonk (talk) 08:02, 19 May 2016 (UTC)

Tony, Exposure isn't facility. I absolutely understand about clutter -- you'll see I mentioned it above. I just think "not in science-related articles... unless there is some special reason" is too sweepingly discouraging of conversions in e.g. descriptions of the visible appearance of familiar animals. Maybe instead "not in technical [or "highly technical"?] sections of article, unless there's some special reason"? Added after edit conflict... And I think, in general, excluding conversions should be the exception, though I'd make it clear it's very much a question of editorial discretion, lest we create a new class of those annoying script-equipped MOS-compliance stormtroopers. EEng 08:11, 19 May 2016 (UTC)

It seems to have more to do with the Wikipedia writers than the readers. The former are about 20 years older than the latter on average, and therefore far more familiar and comfortable with the old measurements. To the younger generation, they are merely used in figurative expressions, without real physical meaning. Just as we still say "penny wise, pound foolish" without knowing how many pennies there was to the pound. Hawkeye7 (talk) 08:40, 19 May 2016 (UTC)

I must object strongly to the previous statement! Despite the jokes about metrication I'm perfectly comfortable with SI units, and if necessary, can do quick "back of a fag packet" calculations in my head to convert units and large and small dimensions into "understandable" quantities. I'd cope quite well if wikipedia was SI only. What I do try to do is use my knowledge of both SI and imperial systems and metrology in general to work out what might be useful to readers - especially US readers who are more familiar with the US customary units. Yes - the US has adopted SI for science and to an extent for engineering. That does not mean that the "average American reader" (regardless of age) is particularly comfortable with SI units (unless they are from an engineering/scientific background).

Back to the main discussion... I actually found it quite hard to find "scientific articles" that had lots of units (with or without conversions) - easier to find in engineering/archictecture articles. I agree with EEng's comment that the current statement is "too sweepingly discouraging of conversions". As far as SI units go, we're talking mainly about the base units for mass, length and temperature, and some of the derived units (newtons, pascals, and joules). All of these can be usefully converted in scientific articles (with the proviso that "highly technical" sections, or sections with lots of measurements don't need to be converted). I'd prefer to see this as one of the bullet points in the MoS rather than a qualifier in the starting paragraph.

Incidentally, looking at the various articles has emphasised how important consistency is (Andromeda Galaxy flits wildly in using parsecs/light years/astronomical units as the main unit), and how important it is to provide some context of size in articles dealing with the very large and very small. Robevans123 (talk) 09:44, 19 May 2016 (UTC)

SIR – Your gratuitous reference to homosexual genitalia mars an otherwise valuable and informative post. ‍—‌ (signed) Disgusted of Tunbridge Wells

Thank you! I never thought I'd laugh out loud at a discussion in MOS:Dates and formats. I shall be renewing my subscription to this esteemed organ. Robevans123 (talk) 12:26, 19 May 2016 (UTC)

Enjoy it while you can, because soon some dyspeptic killjoy will appear to remind us that "We are not here for your entertainment" and "what you think as amusing may not be to others" [4]. EEng 13:37, 19 May 2016 (UTC)

• Urgent comment on previous: "fag" doesn't refer to "homosexual genitalia"; but to (male) homosexuals. It's typically derogatory, if not used ironically or mock-humourously. Tony (talk) 11:45, 20 May 2016 (UTC)

Tony, you're obviously not up on your gay slang. Follow both links in my SIR post above. ‍—‌ (signed) Disgusted of Tunbridge Wells

Ooh, my favourite! Black mm (ins). Martinevans123 (talk) 08:29, 11 June 2016 (UTC)

Let me asking you something, ME123. At family holidays, did they let you eat at the grownups' table? EEng 12:20, 11 June 2016 (UTC)

Seeing as I wrote the text which sparked this discussion, I feel like I ought to chime in. My reasoning for excluding conversions on the millimeter measurements was that these numbers are very small in inches (for example, 1.1 mm is 0.043 in), and add a lot of clutter to the page. When I'm reading an article, I find that conversions everywhere make it more difficult to read, but I understand the necessity in many cases. Being an American, I find inches much more intuitive than millimeters or centimeters, but for very small amounts, like 1.1 mm (0.043 in), the number 0.043 in doesn't really give me an idea of how small that is. However, according to EEng, it does give some readers who wouldn't intuit 1.1 mm an idea, so I think I will include the conversion on "my" page (Cairanoolithus) and I agree with EEng that "in general, excluding conversions should be the exception, though I'd make it clear it's very much a question of editorial discretion". Ashorocetus (talk | contribs) 14:20, 19 May 2016 (UTC)

• So getting back on track, it seems most here can agree that exclusion of conversions should be the exception rather than the rule? Or are there any dissenters? FunkMonk (talk) 15:41, 20 May 2016 (UTC)

The best way to get concrete opinion is to make a concrete proposal for changed guideline wording. (I lack the concentration just now to do that myself.) EEng 15:57, 20 May 2016 (UTC)

By simply re-jigging the current text, I get: "In science-related articles, however, supplying such conversions is not required in special/some cases." Could be followed by an example or two and a rationale: "Highly technical sections with many measurements can become too cluttered if they are all accompanied by conversions. "Clutter" isn't even mentioned in the current text, even though it seems to be the only argument against conversion. And yes, it would work better as a bullet point. FunkMonk (talk) 16:01, 20 May 2016 (UTC)

Proposal A1

Let me suggest that we focus more on the "technical" and "dense" criteria, instead of the vague "science-related".

A1

Where English-speaking countries use different units for the same quantity, follow< the "primary" quantity with the "primary" quantity should usually be followed by a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so. In technical articles, sections, or passages dense with measurements, conversion of every measurement may be of little value and can clutter the text. In such cases editorial judgment will dictate which measurements should and should not carry conversions. Where an imperial unit is not part of [etc etc]

EEng 19:07, 20 May 2016 (UTC)

Looks good to me. Robevans123 (talk) 19:11, 20 May 2016 (UTC)

-- (signed) Satisfied in Southampton. EEng 19:21, 20 May 2016 (UTC)

Second that. FunkMonk (talk) 20:04, 20 May 2016 (UTC)

-- (signed) Seconding in Schenectady. EEng 23:26, 20 May 2016 (UTC)

Proposal A2

This refines A1 a bit, and adds an example. The strikeout/underlining is still vs. the current live guideline. The animal example is made up. The semiconductor example is a bit awkward (but maybe that's the point). Improvements welcome! (Modify in place if the change is immaterial to comments anyone's made.)

A2

Where English-speaking countries use different units for the same quantity, follow< the "primary" quantity with the "primary" quantity should usually be followed by a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so. In scientific/technical articles, sections, or passages dense with measurements, conversion of every measurement may clutter the text to little benefit. In such cases editorial judgment will dictate which, if any, measurements should carry conversions.   •   Adults are typically 13–17 cm (5–7 in) long, with blue or orange eyes, razor-sharp teeth, and a tail 5–8 cm (2–3 in) long. but Typical sizes were about 10 µm (0.0004 in) in 1971, but decreased rapidly through the 1980s (1500–800 nm), 1990s (600–180 nm) and 2000s (130–32 nm). By 2014 sizes as small as 14 nm (0.55 millionths of an inch) were common. Where an imperial unit is not part of [etc etc]

EEng 00:10, 22 May 2016 (UTC)

The semiconductor example is exactly where conversions should not be used. μm and nm to inches? Makes as much sense as converting Earth mass into slugs. Headbomb {talk / contribs / physics / books} 01:33, 22 May 2016 (UTC)

Well, like I said, I know it's awkward. My idea was that sometimes you might convert the first measurement in a series of similar measurements (which, actually, these aren't -- they run through orders of magnitude) to give the reader a sense of size, and then don't bother with the rest. Or in this case, I thought it might make sense to convert the two endpoints, again to let the Imperial numbskull at least grasp how things have progressed; but it just ends up a mess with "millionths of an inch" and so on. Like I said, Improvements welcome!, so please contribute something better. Do you like the orange-eyed creature, though? EEng 02:23, 22 May 2016 (UTC)

P.S. As a gesture toward sanity, A3 removes the conversion of the right endpoint...

Proposal A3

A3

Where English-speaking countries use different units for the same quantity, follow< the "primary" quantity with the "primary" quantity should usually be followed by a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so. In scientific/technical articles, sections, or passages dense with measurements, conversion of every measurement may clutter the text to little benefit. In such cases editorial judgment will dictate which, if any, measurements should carry conversions.   •   Adults are typically 13–17 cm (5–7 in) long, with blue or orange eyes, horrid breath, razor-sharp teeth, and a tail 5–8 cm (2–3 in) long. but Typical sizes were about 10 µm (0.0004 in) in 1971, but decreased rapidly through the 1980s (1.5 µm – 800 nm), 1990s (600–180 nm) and 2000s (130–32 nm). By 2014 sizes as small as 14 nm were common. Where an imperial unit is not part of [etc etc]

EEng 02:38, 22 May 2016 (UTC)

Proposal A4

I love the halitotic, polychromatic bug! The example works.

The second example uses orders of magnitude which confuses the issue. BTW the discussion is also confused by references to slugs - a relatively obscure unit of measurement used only by imperial scientists and engineers. I suspect that the majority of fully metricated readers will also struggle with micrometres and nanometres and, at least on first usage, would probably benefit from a conversion into more familiar units, eg 1 µm (one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch). But that perhaps is outside the scope of this discussion. How about:

  •   Popular model gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 30 mm, and 45 mm (1.77 in).

Robevans123 (talk) 09:23, 22 May 2016 (UTC)

No conversions from within the SI system to SI system. That's why we have SI prefixes in the first place! Headbomb {talk / contribs / physics / books} 13:11, 22 May 2016 (UTC)

What are you talking about? EEng 13:18, 22 May 2016 (UTC)

To quote Robevans123: "I suspect that the majority of fully metricated readers will also struggle with micrometres and nanometres and, at least on first usage, would probably benefit from a conversion into more familiar units, eg 1 µm (one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch)." Headbomb {talk / contribs / physics / books} 14:18, 22 May 2016 (UTC)

Way better! So now we have:

A4

Where English-speaking countries use different units for the same quantity, follow< the "primary" quantity with the "primary" quantity should usually be followed by a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so. In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases editorial judgment will dictate which, if any, measurements should carry conversions.   •   Adults are typically 13–17 cm (5–7 in) long, with blue or orange eyes, horrid breath, razor-sharp teeth, and a tail 5–8 cm (2–3 in) long.   •   Popular model gauges range from 6.5 mm (​0.256 in) to 45 mm (1.77 in). but Popular model gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 25 mm, 30 mm, and 45 mm (1.77 in). Where an imperial unit is not part of [etc etc]

Notice I also cut down the "In scientific/technical articles" bit -- I don't think it's needed -- and elaborated the second example for better contrast. EEng 10:30, 22 May 2016 (UTC)

I think we're getting there. I'd be Delighted of Tunbridge Wells with that. Robevans123 (talk) 11:14, 22 May 2016 (UTC)

Proposal A5

Incorporating some good ideas from B1 (below). The football example, um, didn't turn out as good as I'd hoped, but you get the idea. Maybe someone can improve it, or work up a better example.

A5

Where English-speaking countries use different units for the same quantity, follow< the "primary" quantity with the "primary" quantity should usually be followed by a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so. However, in certain circumstances conversion is inappropriate:   •   such drugs are typically given in doses under 20 mg per day not doses under 20 mg (0.00071 oz) per day (topic area in which conversion is of little value to the reader) In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases editorial judgment will dictate which, if any, measurements should carry conversions:   •   Popular model gauges range from 6.5 mm (​0.256 in) to 45 mm (1.77 in). but Popular model gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 25 mm, 30 mm, and 45 mm (1.77 in). Certain topic areas may benefit from a mixed approach e.g. American football:   •   Games are played on a rectangular field 120 yards (110 m) long and 53.33 yards (48.76 m) wide, with goal lines are marked 10 yards (9.1 m) inward from each end ... Note: This article discusses movements of players and the ball in units of yards (0.91 m), as is standard in the sport. The offense is given a series of four plays, known as downs. If the offense advances ten or more yards in the four downs, they are awarded a new set of four downs. If they fail to advance ten yards, possession of the football is turned over to the defense ... On a kickoff, the ball is placed at the 35-yard line of the kicking team in professional and college play and at the 40-yard line in high school play. In some cases, it may be helpful to provide a sense of scale instead of a conventional conversion:   •   a giant star of radius 61 million kilometres (44 times that of the sun)   •   diameter as small as 14 nm (about 63 silicon-atom diameters)   •   precise assays are possible on samples as small as 0.1 ml (about the size of a pinhead) (Note that a source may be needed for such comparisons, if not allowable under WP:CALC.) Where an imperial unit is not part of [etc etc]

EEng 20:17, 22 May 2016 (UTC)

It's getting a bit like the old joke about economics (how do you get four theories on economics? Put three economists in a room together!). Seriously though, Proposal A5 has merit. I'm going to sleep on it, maybe not even look at it for a couple of days, go write some articles only involving metre/feet conversions, and come back and take another look. The football idea has legs (around 40 if you only include onfield players and officials, more if you include coaches, cheerleaders etc). Robevans123 (talk) 21:03, 22 May 2016 (UTC)

The president of Harvard is meeting with the chairman of the physics department. "You physicists!", he exclaims. "Why do you need all this expensive equipment? Look at the math department‍—‌all they ask me for is paper, pencils, and erasers.

"And the [insert favorite department name here – economics, psychology, philosophy] department‍—‌they don't even want erasers!"

EEng 01:18, 23 May 2016 (UTC)

I'll just add here that I'm in favour of any proposal that makes exclusion of conversions the exception rather than the rule, I don't have much to say about the exact details, but what I see here looks good. FunkMonk (talk) 21:55, 22 May 2016 (UTC)

No doubt comments from others will help improve this even more. EEng 01:18, 23 May 2016 (UTC)

I'd quibble some of the examples given. I find it rather more interesting and instructive that the radius of the giant star is about 0.41 Astronomical units (otherwise put, 41% of the mean Earth-Sun distance) than that it's 44 solar radii, and I wonder how many people are going to find it useful to learn that 14 nanometres is the diameter of 63 silicon atoms. In context, sure, it may be appropriate, but if it's a context-specific choice we need to give the context in the guideline. Overall though, the reason I haven't got involved before now is that I'm broadly happy with the way this is going.

I can also see some people might start getting hung up on double decker buses, or areas the size of Wales. Kahastok talk 20:09, 23 May 2016 (UTC)

Um, I'm finding that last bit about the buses and so a bit obscure. EEng 15:13, 25 May 2016 (UTC)

Proposal A6

Taking Kahastok's comments on board, and putting the football example on a further diet...

A6

Where English-speaking countries use different units for the same quantity, the "primary" quantity should usually be followed by a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. However, in some circumstances conversion is inappropriate:   •   such drugs are typically given in doses under 20 mg not under 20 mg (0.00071 oz) (topic area in which conversion is of little value to the reader) In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases editorial judgment will dictate which, if any, measurements should carry conversions:   •   Popular gauges are 6.5 mm (​0.256 in), 30 mm (1.18 in), and 45 mm (1.77 in). but Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in). Certain topic areas may benefit from a mixed approach e.g. American football:   •   Games are played on a rectangular field 120 yards (110 m) long and 53+1⁄3 yards (48.8 m) wide, with goal lines are marked 10 yards (9.1 m) inward from each end ... Note: This section discusses movements of the ball in units of yards (0.91 m), as is standard in the sport. On a kickoff, the ball is placed at the 35-yard line of the kicking team (the 40-yard line in high school play). If the offense advances ten or more yards in the four plays, they are awarded a new set of four plays. If they fail to advance ten yards, the ball is turned over to the defense ... In some cases, it may be helpful to provide a sense of scale instead of a conventional conversion:   •   a giant star of radius 61 million kilometres (44 times that of the sun) or a giant star of radius of 61 million kilometres (41% of the mean Earth-Sun distance)   •   fabrication of semiconductor devices as small as 14 nm (about 63 silicon-atom diameters)   •   precise assays are possible on samples as small as 0.1 ml (about the size of a pinhead) (Note that a source may be needed for such comparisons, if not allowable under WP:CALC.) Where an imperial unit is not part of [etc etc]

EEng 05:41, 25 May 2016 (UTC)

This is looking really good. I'm going to nit-pick like mad so that maybe the final step on this journey is Edinburgh to Carlisle (A7)...

Intro sentence:

Where English-speaking countries use different units for the same quantity, the "primary" quantity should usually be followed by a conversion in parentheses, for example: the Mississippi River is 2,320 miles (3,734 km) long, or (from Australia) the Murray River is 2,508 kilometres (1,558 mi) long.

Rationale: This lead has always bugged me - the semi-colon in black is really hard to spot so it looks like the two examples are from one article.

Drug example:

• WorldMegaPharma had to withdraw the blister packs of 20 mg tablets not 20 mg (0.00071 oz) (topic area in which conversion is of little value to the reader and drug dosages are now widely given in mg)

Rationale: While originally researching this conversion I found that WikiProject Pharmacology avoids giving dosages except in general discussions (Wikipedia:Medical disclaimer), and the US press regularly uses mg without conversions.

Model scale example: - Perfick!

American football example: - just a small copy edit - ...with goal lines are marked...

Sense of scale:

• In some cases, it may be helpful to provide a sense of scale in addition to, or instead of, a conventional conversion:

Rationale: Where common units are used, for example, kilometres, but with a very large value, then it's still useful to include a metric/US customary conversion as well, for example, a giant star of radius 61 million kilometres (38 million miles, or 44 times that of the sun) - don't know if the convert template can cope with this... The small scale examples are absolutely appropriate for the context.

And finally, I think Kahastok was warning on using unusual units such as:

• The asteroid's largest crater is about the size of Wales. Do not use conversions that may be confusing or unknown to the lay reader.

Rationale: Although this and other unusual units may be meaningful to regional audiences they may not play in Peoria, just as "The asteroid's largest crater is about 6.5 times the size of Rhode Island" wouldn't play in Pontypool.

Robevans123 (talk) 19:52, 25 May 2016 (UTC)

Proposal A7

Integrating Robevans123's excellent nitpicks, though with a different solution for the river-semicolon problem, and various other adjustments -- anyone, feel free to adjust/change in place, as long as doing so doesn't make any comments already made hard to understand. (Later: also integrating Robevans123's later material on the giant star example.)

A7

Where English-speaking countries use different units for the same quantity, the "primary" quantity should usually be followed by a conversion in parentheses:   •   the Mississippi River is 2,320 miles (3,734 km) long (American topic)   •   the Murray River is 2,508 kilometres (1,558 mi) long (Australian topic) However, in some circumstances conversion is inappropriate:   •   United Consolidated Amalgamated Intergalactic GigaPharma Ltd. withdrew its 20 mg tablets not its 20 mg (0.00071 oz) tablets (topic area in which conversion is of little value to the reader) In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases judgment will dictate which, if any, measurements should carry conversions:   •   Popular gauges are 6.5 mm (​0.256 in), 30 mm (1.18 in), and 45 mm (1.77 in). but Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in). Certain topics may benefit from a mixed approach e.g. American football:   •   Games are played on a rectangular field 120 yards (110 m) long and 53+1⁄3 yards (48.8 m) wide, with goal lines marked 10 yards (9.1 m) inward from each end ... Note: This section discusses movements of the ball in units of yards (0.91 m), as is standard in the sport. On a kickoff, the ball is placed at the 35-yard line of the kicking team (the 40-yard line in high school play). If the offense advances ten or more yards in the four plays, they are awarded a new set of four plays. If they fail to advance ten yards, the ball is turned over to the defense ... In some cases, it may be helpful to provide a sense of scale instead of, or in addition to, a conventional conversion (though a source may be needed for such comparisons, if not allowable under WP:CALC):   •   fabrication of semiconductor devices as small as 14 nm (about 63 silicon-atom diameters)   •   precise assays are possible on samples as small as 0.1 ml (about the size of a pinhead)   •   a giant star of radius 257 million kilometres (160 million miles, about 370 times the radius of the sun and 1.72 times the mean Earth-Sun distance) but not   •   Ash covered some 170,000 km2 (66,000 mi2, or about the area of Florida) (Scale comparisons should have concrete meaning for most English-speaking readers, and should not be the closest match from an arbitrary list of candidates.) Where an imperial unit is not part of [etc etc]

The "large list of candidates" wording needs work. (I needed to switch to Florida from Wales to make the "list of candidates" point.) On the giant star, we now have three conversions in the mix -- miles, radius of the sun, au. I think two is the max, and here I've used miles and au; but personally I wonder if radius-of-sun and au wouldn't be better. EEng 05:21, 26 May 2016 (UTC)

Was looking at the giant star example and writing an alternative, and then edit-conflicted, but this is what I had:

{{convert}} can sometimes cope with three units (useful when you've got different US/Imperial units that are different but doesn't work for kilometres), but agree that it's not ideal and can be a bit cluttered. I found this description of star size units (in an article, not a style guide...), but it does seem to be sensible and matches some giant star examples.

Taking an example from R Doradus (a red giant) The estimated diameter of R Doradus is 515 ± 70 million km (3.46 AU) or 370 ± 50 times the diameter of the Sun. but gives the radius as 370 ± 50 R☉ in the infobox (only R☉, solar radius, is wikilinked to a definition).

There a few problems with this in that although AU (astronomical unit) is purely a measure of length it is based on a radius (mean Earth-Sun distance) so it's a bit like comparing the diameter of a basketball ball with the radius of a baseball ball. Also R☉ and AU are not particularly common units unless you an astronomer. I think I'd favour a statement like:

• The estimated radius of R Doradus is about 370 R☉ (solar radius), or 1.72 astronomical units.

Or possibly, adding a sense of scale, something like:

• The estimated radius of R Doradus is about 370 R☉ (solar radius), or 1.72 astronomical units (mean Earth-Sun distance), which is about 257 million kilometres (160 million miles).

Which also gives a good idea that if we were going around R Doradus we'd be fried!

BTW - happy with the tweaks that EEng has done to the rest of the proposal. Definitely better splitting the American/Australian examples into bullets.

I think the conversions are ok - will check them again though. For the sake of clarity I've ignored the ± variations.

Robevans123 (talk) 22:47, 26 May 2016 (UTC)

Stellar conversion examples are all correct now.

{{convert}} doesn't support R☉ (solar radius) - will put in request for that. Robevans123 (talk) 23:48, 26 May 2016 (UTC)

My blood sugar is a bit low, but I took your last version re giant star and (jiggling it around a bit) integrated it into A7. I couldn't find a way to use the R☉ symbolism and keep the wording natural. As always feel free to modify in place so long as that doesn't make comments already made hard to interpret. Also, though I left in the miles conversion for the star, I think it's an interesting question whether it's necessary. Even the unmetricated know that a shitload of kilometers is also a shitload of miles, and I wonder whether giving the actual size of the miles shitload tells them much, especially given the presence of the scale comparisons.

Where is everybody???' EEng 00:40, 27 May 2016 (UTC)

I think the stellar example is now fine (it was trying to do too much with conversions and a quick intro to the units at the same time), especially as the article just gives that sort of distance once. I looked at main sequence, which describes one of it's main units (solar mass, M☉) fairly well, and then just uses it. Interestingly, it doesn't offer any equivalent or comparable masses, and for the life of me, I can't think of any (cars 1-2 tonnes, locomotives 50-100 tonnes, large aircraft ~500 tonnes, aircraft carrier ~80,000 tonnes, and then there's a massive leap up to earth's mass ~6 x 10²¹ tonnes)

I think it's better to leave the miles in - if it's worth stating in kilometres then it's worth stating in miles. Having been interested in astronomy from the age of 9 I have had 93 million miles as the mean Earth-Sun distance in my mind for 50 years (you do the math(s))..., but I accept that it's really difficult to work out what will be useful to readers with different backgrounds.

I do think it is important that we introduce an element of exactitude to shitloads though. We could start off with MegaShitloads, KiloShitloads, Shitloads, MilliShitloads, and MicroShitloads, and see if that's enough... Robevans123 (talk) 09:39, 27 May 2016 (UTC)

I have arrived somewhat late to this discussion, at a stage when it's already ballooned to the point of being hard to follow. I have one pedantic comment here: it's not obvious why you'd ever want to convert milligrams to a fairly meaningless decimal-dust-laden number of avoirdupois ounces – if it was desirable to provide an "old money" equivalent for such a prescription then it would be in apothecary units, something like 20 mg (5⁄16 gr). This is not the sort of thing the MOS needs to have a rule about. But in any such case, providing a conversion is surplus to requirements, I think, since the "old money" there is quite deprecated.

By an extension of this argument, I don't particularly see the point in converting stuff in science articles at all since it's not representative of standard scientific practice (and it is such standard practice which the MOS is supposed to be based on). A reputable scientific source would not detail the LHC in anything other than SI units (and "friends" such as the electronvolt); converting the length to miles and furlongs and whatnot, or the temperature to Fahrenheit or Rankine or other obsolete scales, or converting the energy stored in the ATLAS magnetic field to pound-feet, is excessive and it does not really provide additional useful information. Whatever the primary unit (in WP or real life), an SI equivalent should always be provided, but I do not think the "old money" should be used at all outside of contexts where it has not yet been deprecated. Archon 2488 (talk) 10:54, 27 May 2016 (UTC)

"since it's not representative of standard scientific practice" Wikipedia is not a science journal, our target audience is mainly lay readers. As Robevans123 copied from the Pharmacy project guidelines earlier: "Finally it is important to keep in mind that we are writing a general encyclopedia, intended to be read by the lay public so it is important to make technical material as accessible as possible to a wide audience but at the same time, not reducing the value of the article to more technical readers including medical doctors, pharmacists, and scientists." Adding conversions is win-win, it is not as if we are reducing the value for anyone. FunkMonk (talk) 11:00, 27 May 2016 (UTC)

"our target audience is mainly lay readers" is true in broad outline, perhaps, but I doubt many lay people want to read about Fermi's golden rule. I have no idea how you would even format such an article for a lay audience, or whether it would be desirable to do so. In its science articles, I'd argue that WP already de facto follows scientific conventions for most things (including, for example, using standard technical terminology without excessive glossing).

My point is that excessive conversions are comparable to such excessive glossing. If someone reading an article about zoology is not expected to need terms like "mammal" to be glossed (certainly not on every occurrence) then I don't see why terms like "centimetres" need to be de facto glossed by a convert template. It's fine to argue that it doesn't detract – adding stuff doesn't detract, sure, but it clutters things unnecessarily. Converting light wavelengths in nanometres to microinches (!) would be one such excessive addition – a unit which would almost never see use in any real-world reputable source from this side of the 1970s, certainly. Fact is, in scientific contexts, measuring temperatures in Fahrenheit is almost unheard of, and one might argue that mandating its use would be incompatible with WP:NPOV. So it's not as simple as "win-win"; there is a necessary discussion about when such conversions are useful at all, and when they are excessive.

My standard rule would be: if there is some real-world reason, in line with NPOV, why some non-SI unit would be relevant, then it may be provided in brackets, but otherwise the style guidance should be to omit it. For example, it might be desirable to point out that the reason why a gamma camera scintillator crystal has a rather odd thickness of 9.525 mm is that it was historically 3⁄8 inch, but this would not be a reason to convert all millimetres to inches in such an article. Archon 2488 (talk) 11:20, 27 May 2016 (UTC)

I think the point here is mostly geared at the question, what is science? I think the balance here is correct, but I don't think we're coming at this from massively different directions. Because I think a lot of the concerns you express are already addressed by the proposed guideline. We start this proposal by saying:

“ Where English-speaking countries use different units for the same quantity, the "primary" quantity should usually be followed by a conversion in parentheses... ”

and we say something similar in the standing version of the guideline. Clearly, if English-speaking countries use the same unit, this doesn't apply. It also makes it clear that in topic areas "in which conversion is of little value to the reader", "conversion is inappropriate". I find it difficult to see how hard science - including your examples of the wavelength of light or the thickness of a gamma camera scintillator crystal - would not clearly be excluded from conversions by these two rules. Everyone uses the same units and conversion is of little value to the reader.

But there are areas where science meets more general interest. These areas where there is likely to be a genuine difference between lay readers in different countries and I see no reason not to give both versions where it does not detract from what we say. For example, when it comes to the length of an animal, it seems odd and unnecessary to refuse to provide conversions. And I think this proposal provides a number of good examples of where it may detract or be unnecessary to provide conversions and where it is likely to be desirable. Kahastok talk 17:28, 27 May 2016 (UTC)

• It is interesting that Archon and I noticed the same thing, but I strongly object to the 20mg to ounces conversion. That would never have been used, as one would've likely used grains for that purpose. Of course, the grain conversion is absolutely useless to our readers, so I'd say that it provides a good example of when not to use a conversion. Scrap ounces, put in grains. RGloucester — ☎ 15:40, 27 May 2016 (UTC)

An interlude

• Um, "I strongly object to the 20mg to ounces conversion" -- huh? The drug example says not to make that conversion.
• The current guideline says,

Where English-speaking countries use different units for the same quantity, follow the "primary" quantity with a conversion in parentheses

A7 weakens this substantially:

Where English-speaking countries use different units for the same quantity, the "primary" quantity should usually be followed by a conversion in parentheses

This is a substantial movement toward "conversion's optional", so I'm not sure why some people are worried that conversions will be popping up in inappropriate places. Nonetheless let me suggest this alternative, which implies conversion as the default, while still making very clear that not converting may be perfectly fine as well:

Where English-speaking countries use different units for the same quantity, the "primary" quantity will typically be followed by a conversion in parentheses

• Finally, I'd like to change the inappropriate-to-convert section to this (updated per RGloucester, below):

However, in some circumstances secondary units are unknown or obsolete in the topic area, and of little or no value to the reader:

  •   United Consolidated Amalgamated Intergalactic GigaPharma Ltd. withdrew its 100 mg tablets not its 100 mg (0.00353 oz) tablets nor its 100 mg (1.54 grain) tablets

  •   Visible light is usually defined as having wavelengths in the 400–700 nm range not the 400–700 nm (14.75–27.56 μin) range

Would this help? EEng 04:20, 28 May 2016 (UTC)

I was simply saying that an mg to oz conversion is a bad example because it doesn't make any sense, as the two units are not equivalent in use. The equivalent would've been grains, not ounces, as I'm sure you've figured out. A grain conversion, while correct, would be "of little or no value to reader", as the grain is no longer used. On the other hand, the ounce was never used for measuring a tablet of some drug, and usage in this instance is simply wrong. Do you understand the distinction, i.e. between a correct but disused conversion and a nonsense conversion? RGloucester — ☎ 04:32, 28 May 2016 (UTC)

Sorry, I was using my mouse-brain by mistake. I've modified the example above. I'm assuming you have an abacus that works in grains so please check my math. EEng 09:09, 28 May 2016 (UTC)

The convert template does actually support grains, as I showed above. So 100 mg (1.54 gr) or 100 mg (1+9⁄16 gr) (the latter probably makes more sense when using Ye Kynge's Moste Olde Measures, but to press that point would be rather like arguing about the gender of the angels since these units are so totally deprecated). Also, I don't think that the ersatz symbol "μin" is permitted by the MOS in any case. Convert just gives it in scientific notation: 400–700 nm (1.6×10⁻⁵–2.8×10⁻⁵ in). Another pedantic niggle here: the first part of your conversion to microinches seems to be wrong: should be 15.75 rather than 14.75. My advice would just be to put these in via the convert template since that is how they'd likely manifest in an article, should someone try to add them.

(A discussion for another day would be why convert supports deprecated units like the grain that we are in effect telling people not to use – in those incredibly rare cases where you had, say, a quantity defined in grains, you could just do the conversion manually. One might argue that putting in unnecessary units might just encourage people to use them without justification, hence leading to the kind of unit proliferation we're trying to avoid.) Archon 2488 (talk) 13:27, 28 May 2016 (UTC)

The one article where I know that the grain appears in is aspirin. RGloucester — ☎ 15:07, 28 May 2016 (UTC)

The idea of restricting template interfaces to coerce MOS compliance comes up a lot in the context of {{cite}} and so on. I think it's a bad idea. It's a bit paternalistic, and you can certainly imagine situations (e.g. a discussion of the history of pharmacy) where it's somehow needed. EEng 15:36, 28 May 2016 (UTC)

The aspirin article was the only drug-related article I could find that included a grain conversion, and in that particular usage the conversion to grains is entirely reasonable - as it's explaining the history of the size of aspirin doses. As I've mentioned elsewhere the WikiProject Pharmocology style guide deprecates details on dosages generally, but allows it in general discussions (this is what prompted the example of a drug being recalled, based on a real article). I think the drug example stands as an example of both a nonsense conversion (where it could be regarded as an attempt to put the value into imperial/US customary units, in an area where people everywhere probably think of drug doses in mg), and also an example of a conversion into an effectively obsolete unit (in the context of drug doses where even the US would appear to be fully metricated), but see later note on obsolete/deprecated units below. BTW if you look at the description photo (from 2007) of an aspirin bottle used in the article, the contributor claims the image shows that common dosage is 5 grains (325 mg) when the label actually reads 325 mg (5gr) - looks like a last stand against metrication of drugs in the US!

While googling around on the subject of grains and drugs I did notice that the recreational drugs market is not fully metricated yet! This useful source shows 24 uses of US customary units, 13 metric units, and two unusual units (brick and half a football field)!-;)

Also, we need to be careful about classifying a unit as deprecated as opposed to obsolete. A unit may be deprecated in some areas, but it may well still be in common usage. For example, the Guide for the Use of the International System of Units (SI), published by NIST, deprecates ppm, ppb, and ppt, but recognises that these may be required by a law or a regulation (page 30). And I note that ppm is used in a number of scientific articles (for example Proton nuclear magnetic resonance, which is a good example of why we shouldn't adopt style guides from external agencies (although they can be a useful source of information on units).

BTW the grain is still the standard unit for the weight of bullets (there are hundreds of pages that describe bullets and give the weight in grains), so it could not even be described as an obsolete unit...Robevans123 (talk) 17:27, 28 May 2016 (UTC)

Let's put in a request for {{convert}} to handle keys of cocaine, tabs of acid, lids/dime bags of pot, and so on. EEng 17:56, 28 May 2016 (UTC)

A good idea. You'd also need to provide data on the tolerance of weights etc, and also assay values on the quality, as I understand these values are rather less precise than the values you might expect in science articles. Robevans123 (talk) 18:07, 28 May 2016 (UTC)

• Except for science-based articles, which can use international units alone, conversions should on no account be optional—especially international units after a British Empire unit. Tony (talk) 15:37, 28 May 2016 (UTC)

Do you really mean that? So in Super_Bowl_XIX you want all that talk of who had how many rushing yards (or whathaveyou) --

San Francisco defensive back Dana McLemore returned the ball 28 yards to the 49ers 45-yard line. After advancing 15 yards with two running plays, Montana completed a pair of passes to tight end Russ Francis to move the ball 29 yards to the Miami 11-yard line.

converted into meters?EEng 16:10, 28 May 2016 (UTC)

User:Tony1 - can you provide examples of scientific articles where the conversion of some units, at least to give a sense of scale, would be detrimental to the article? As noted, the american football example is a good example of where you might only convert a unit on first use, and then stick to primary unit, and this might apply equally where the primary unit is US customary/imperial or metric. Robevans123 (talk) 17:27, 28 May 2016 (UTC)

More pedantic comments on my part: "conversion" and "sense of scale" are different. Converting the mass of an asteroid from kilograms to pounds or stones or hundredweights is pointless; relating its mass to that of the moon or the earth might provide a useful sense of scale. This is what is done, for example, in the article on Ceres. I am wary of introducing any phrasing that might endorse routine conversion of SI to imperial in the context of science-related articles. For that reason, I also would dispute the wisdom of asking "is there any example of when conversions are detrimental?". What we're trying to do here is put a brake on excessive conversions in science articles, so I'd argue that that is not the angle from which we want to approach things. Similarly, WP does not accept "there is no detriment to having an article on this" as an argument not to delete an article. Simply because we can put something there doesn't mean we ought to.

I would argue that there are extremely few cases where it would be desirable or even permissible to have an article in imperial or USC without conversion. The use of yards in American football is used as almost the sole example, for a good reason. It is a topic which is almost exclusively of interest to Americans, and it uses USC units exclusively. Therefore a deviation from the normal requirement for an explicit SI conversion every time is permitted. But I doubt there are many other topics where these conditions are met. Archon 2488 (talk) 19:07, 28 May 2016 (UTC)

Yes, I think "is there any example of when conversions are detrimental?" is a good question, and yes, I think there are good examples where it will be, such as the wavelength of light in the proposed change.

If we're allowed to use SI without conversion then it stands to reason that where similar circumstances arise with non-SI unit we should be allowed to use those non-SI units without conversion. It seems bizarre to insist on conversions no matter what in one direction, and not to similarly insist on conversions the other way. That is not, of course, to say that these circumstances will be as common with imperial or US customary units as they are in SI.

FWIW, another example is maritime law, yet another might be height of aircraft. In topics dense with these measurements, you wouldn't want to convert every measurement. And of course SI does not formally accept any time period longer than a day, but we're never going to have articles that routinely provide conversions into seconds (or even Megaseconds or Gigaseconds). Kahastok talk 19:39, 28 May 2016 (UTC)

They're not symmetric situations (imperial/USC to SI and vice versa), for a couple of reasons. Firstly, the legacy units have no existence independent of SI; one cannot even speak of "inches" without implicitly invoking SI standards, whereas the converse is obviously false. Secondly, SI is an international standard, and the normal system in use on WP, and the normal system of units in use in virtually every country on Earth, whereas the old money is decidedly none of those things.

For aviation altitudes, one typically encounters a mixture of feet and metres in sources (since in most countries feet are archaic and deprecated outside of this single context). Moreover, for comparison with terrain elevations (normally in metres in every country except the USA, I think), and to speak to people under retirement age in a language they understand, a conversion to metres is useful. Similarly, nautical miles are a "jargon" unit, like the AU, which should be converted since they are of little direct meaning to most people. If I'm confronted with a number of nautical miles I just double it in my head to get a rough number of kilometres, for example.

I don't know why SI doesn't accept the week if it accepts minutes, hours, and days, but the (calendar) month and year are obviously not of consistent length, so I assume that is the reason. In any case, I think there is little chance that megaseconds or gigaseconds will be used in articles, so I don't find this especially relevant. Archon 2488 (talk) 20:05, 28 May 2016 (UTC)

I don't think anyone who's been in these discussions does not know that you prefer metric measures. Your preference does not override the likely preferences of a large proportion of our readers. Do you really think people in the US retire before they finish school?

Yes, it's helpful to convert in most cases, but if you're describing air manoeuvres in detail - particularly in a place where land elevation is not significant - you're probably not going to want to put a conversion on every single altitude, which is what you seem to be proposing. Similarly nautical miles in maritime law. Similarly yards in American football as in the proposal. In the case of the non-SI light year and parsec - that's a clear scientific context - you're unlikely to want to convert to SI units at all. You say the year is irrelevant and you airily dismiss the Gigasecond and Megasecond, but if there always has to be a conversion to SI they have to be there.

Where English-speaking countries all use the same non-SI measure, where the SI measures are unknown or obsolete, where imperial-first text is dense with measurements, and in all the other circumstances we allow unconverted SI units, it seems bizarre not to allow the unconverted non-SI unit equivalently. And I must admit I can't for the life of me see how that could be controversial: the idea that we should feel the need always to have a conversion to SI for every non-SI unit, no matter how well used the SI and non-SI units are, no matter whether the SI units are relevant, no matter what all those conversions do to the article, is frankly absurd. Kahastok talk 21:08, 28 May 2016 (UTC)

There's a certain amount of misrepresentation going on there. Firstly, we're not talking at all about US-related non-science articles (or at least I wasn't) and we're now getting quite off-topic. Secondly, we're not talking about my personal preferences (or at least I wasn't, so thanks for trying to derail the discussion onto that topic).

Given that WP always converts miles to kilometres in US articles, I do not accept that feet in aviation or nautical miles are any different.

I did not say years were "irrelevant" (that is your word, not mine, and I do not accept it as a paraphrase of my argument); I said that because a year is not a unit of consistent length, that is probably why it is not listed as a unit in the SI brochure. I did not "airily dismiss" megaseconds and gigaseconds (and I don't understand why you think those unit names need to be capitalised). I observed that there is no practical reason why such units would be used on WP, and I do not think MOS discussions should revolve around scenarios which do not occur in practice. Absent some real dispute in article-space about the merits of years versus gigaseconds, there is no purpose in discussing the topic at the level of MOSNUM. In this sense, only, my position could be stated as "years versus gigaseconds is an irrelevant dispute". Please stop misrepresenting me.

In relation to some of the other points you raise: firstly, I don't know of any instances where an SI unit is "obsolete"; SI was designed to replace older systems of measurement, so that doesn't really make sense. It's sort of like saying that horse-drawn carriages might one day deprecate battery-electric autonomous vehicles. Policies on when to provide specific conversions might be better decided at the topic/project level (e.g. American football) than the MOS level, however. I was not arguing that the MOS should require an absence of conversions; that is too paternalistic, to use EEng's word. In practice, if editors protest the lack of conversions, then in most cases they will be added. Archon 2488 (talk) 21:53, 28 May 2016 (UTC)

• I think we should be careful about making comments like a certain amount of misrepresentation going on there. Probably best to just correct and/or clarify. If not, I'll start making comments on fallacious arguments like or the temperature to Fahrenheit or Rankine or other obsolete scales, which is classic example of False equivalence, as although Rankine is a pretty much forgotten obsolete scale, Fahrenheit is the most commonly used temperature scale in the US, and still survives to a lesser extent in countries that have been metricated or semi-metricated. Of course it may just be that the editor was just not aware of the use of Fahrenheit, in which case I apologise, or it could have just been a cheap debating trick. But it's probably best to let the participants make their own judgements... -;) Robevans123 (talk) 22:40, 28 May 2016 (UTC)

Clarification: in this context we are talking specifically about science articles, not (for example) how one would report the weather in the US. Rankine is still used, in fact, in some US engineering applications. However, I would not expect a paper in the New England Journal of Medicine to describe human body temperatures in anything other than degrees Celsius (for example). In the context in which my comments were made, they were not a false equivalence or a misrepresentation. Archon 2488 (talk) 23:21, 28 May 2016 (UTC)

Fair enough - gone back and read in detail - my bad. Sorry - only just noticed your edit above.Robevans123 (talk) 15:08, 29 May 2016 (UTC)

And yet you are arguing for a difference in treatment. We should always convert non-SI to SI, but not vice versa, even if equivalent situations arise. This is a daft idea. You dismiss the time point again, but fail to rebut it. A time period of 100 years is not SI. If all non-SI units must be accompanied by a conversion into SI then that cannot not include a period measured in years. Are you proposing to convert 100 years to 36.5 kilodays instead? 877 kilohours?

I think that when the same circumstances arise, the same outcome should result, whether the primary unit is SI or non-SI. Just as we do not convert SI when all the English-speaking world use SI, so we do not convert a non-SI unit when it is used by all the English-speaking world. Just as we do not convert into non-SI units unknown or obsolete in the topic area that are of little or no value to the reader, so we do not convert into SI units unknown or obsolete in the topic area that are of little or no value to the reader. Just as in texts dense with measurements we do not convert every single measurement into non-SI units, so in texts dense with measurements we do not convert every single measurement into SI units. Try as I might, I still can't see how that concept could be in any way controversial.

(And the fact that SI was designed to replace older systems of measurements does not mean that its units cannot be obsolete. The cgs system was also designed to replace older systems of measurement - does that mean that the erg, the dyne and the gal are not obsolete? But that's beside the point.) Kahastok talk 22:26, 28 May 2016 (UTC)

(ec) SI units will not be obsolete until and unless a replacement for SI is devised, at some hypothetical point in the future. Until that happens, there is no merit in entertaining such an idea here. This is another argument which is not based on a realistic scenario.

In the case of time, you're arguing against a position which nobody is advocating (that I can tell). This is the definition of a strawman. To clarify: I am not arguing that we should replace litres with cubic decimetres simply because the latter is SI and the former is not. I have told you several times before that I am not arguing for kilodays or kilohours, and I find it somewhat obnoxious and tedious that you keep bringing it up. Given that you are literally the only person who seems to have a problem with this, you can safely assume that it will never be a problem in the real world.

(And, please, "daft" and "bizarre" do not belong in a constructive discussion. If you're gonna accuse other people of "airily dismissing" others' opinions, don't do it yourself.) Archon 2488 (talk) 23:21, 28 May 2016 (UTC)

• To focus discussion, I suggest that people please crystallize any concerns they have in terms of specific text from A8 which they're concerned about, or in terms of specific suggested changes/additions. Please do that in the A8 section (below).' EEng 23:12, 28 May 2016 (UTC)

Proposal A8

• Apparently μin is legit [5]
• I've switched the grains to fractions to make it more quaint
• Note the new phrasings the "primary" quantity will typically and in some circumstances secondary units are unknown or obsolete in the topic area

Here's A8, based on all the above (and later extended/modified as detailed in the collapse section below):

A8

Where English-speaking countries use different units for the same quantity, the "primary" quantity will typically be followed by a conversion in parentheses. Generally, conversions to and from metric units and US or imperial units should be provided:   •   the Mississippi River is 2,320 miles (3,734 km) long (American topic)   •   the Murray River is 2,508 kilometres (1,558 mi) long (Australian topic) However, do not convert where it would make a common or linked expression awkward (The four-minute mile). In some circumstances secondary units are unknown or obsolete in the topic area, and of little or no value to the reader:   •   United Consolidated Amalgamated Intergalactic GigaPharma Ltd. withdrew its 100 mg tablets not its 100 mg (1+9⁄16 gr) tablets and definitely not its 100 mg (0.00353 oz) tablets   •   Visible light is usually defined as having wavelengths in the 400–700 nm range not the 400–700 nm (15.8–27.6 × 10-6 in) range In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases judgment will dictate which, if any, measurements should carry conversions:   •   Popular gauges are 6.5 mm (​0.256 in), 30 mm (1.18 in), and 45 mm (1.77 in). but Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in). Certain topics may benefit from a mixed approach e.g. American football:   •   The field is rectangular, 120 yards (110 m) long and 53+1⁄3 yards (48.8 m) wide, with goal lines marked 10 yards (9.1 m) inward from each end ... Note: This section discusses movements of the ball in units of yards (0.91 m), as is standard in the sport. On a kickoff, the ball is placed at the 35-yard line of the kicking team (the 40-yard line in high school play). If the offense advances ten or more yards in the four plays, they are awarded a new set of four plays. If they fail to advance ten yards, the ball is turned over to the defense ... Where an imperial unit is not part of the US customary system, or vice-versa – and in particular, where those systems give a single term different definitions – a double conversion may be appropriate: Rosie weighed 80 kilograms (180 lb; 12 st 8 lb) (markup: {{convert|80|kg|lb stlb}}); The car had a fuel economy of 5 L/100 km (47 mpg‑US; 56 mpg‑imp) (markup: {{convert|5|L/100km|mpgus mpgimp|abbr=on}}). In some cases, it may be helpful to provide a sense of scale instead of, or in addition to, a conventional conversion (though a source may be needed for such comparisons, if not allowable under WP:CALC):   •   fabrication of semiconductor devices as small as 14 nm (about 63 silicon-atom diameters)   •   precise assays are possible on samples as small as 0.1 ml (about the size of a pinhead)   •   a giant star of radius 257 million kilometres (160 million miles, about 370 times the radius of the sun and 1.72 times the mean Earth-Sun distance) but not   •   Ash covered some 170,000 km2 (66,000 sq mi, or about the area of Florida) (Scale comparisons should have concrete meaning for most English-speaking readers, and should not be the closest match from an arbitrary list of candidates.) Converted quantity values should use a level of precision similar [etc etc]

EEng 15:36, 28 May 2016 (UTC)

Resolved minor points

I'm confused by the word "legit" here – the fact that you can find a source that uses that notation does not, by itself, prove anything. As far as I can tell, MOSNUM does not presently allow the use of SI prefixes with imperial/USC units (unlike with SI, there are no universally accepted standards for the use of the old units, so every field, and potentially every author, can adopt their own convention). So a notation like "μin" would be impermissible on Wikipedia in any case. The ambiguity here is that the current phrasing suggests such notations would ever be acceptable, rather than simply saying that they are redundant in this case. Similarly, the made-up symbol "mi2" is AFAIK not supposed to be used on WP. It's maybe beyond the scope of this discussion, but I firmly oppose the use of SI prefixes with non-metric units, since this is likely to cause confusion. If for some reason people want to convert distances in the solar system to miles, made-up symbols like "Mmi" and "Gmi" should not be used. If there is any confusion over this point, we should discuss and add an entry to the "Prefixes" section of the relevant MOSNUM table. Archon 2488 (talk) 17:20, 28 May 2016 (UTC) If you prefer "microinches" over μin then you could have just edited A8, as I'm doing here, with an edit summary indicating that you think μin is a bad idea. No need for everything to be laboriously talked out here -- be bold. The other stuff really is out of scope here. I'd really consider it a favor if you could say what you think about A8 overall EEng 17:54, 28 May 2016 (UTC) Sorry, my usual approach is to pedantically pick holes in the bits that I don't like. I leave it as implicit that I approve of the stuff that I don't niggle about. I don't really disapprove of saying that something is "about the area of Florida", but I get the feeling that that's a can of worms. Archon 2488 (talk) 19:28, 28 May 2016 (UTC) No worries. At another project page recently progress was obstructed by an admin with a distorted idea of what constitutes consensus [6] and I didn't want a similar fate to befall this effort just for lack of explicit approval. EEng 21:34, 28 May 2016 (UTC) This is embarrassing, but I had been thinking the text we were discussing was a replacement for only the first paragraph (non-bulletted) of the current section i.e. to replace from "Where English-speaking countries use" to "some special reason to do so". I completely missed that the two bullets (especially the second of them) immediately after that first paragraph already addressed what we're discussing here, to some extent. In particular I didn't realize that Am. football was already being used as an example. I just wasn't looking. This also explains some of what Headbomb and Tony1 comments which had puzzled me. Anyway, since A8 hasn't got any significant comment, I've integrated those two bullets into it, which I hopes makes it more appealing for all parties. Sorry for the confusion. Are we getting anywhere? EEng 18:22, 28 May 2016 (UTC) I have changed "mi2" to "sq mi" (as is more conventional) and got rid of microinches in favour of scientific notation I believe more closely matches what we would in practice use. There is no good conventional imperial unit at this magnitude because nobody uses imperial units at this magnitude, and I share reservations about microinches. If this is controversial or undesirable, please feel free to revert. Beyond this, I am broadly happy with this proposal. Kahastok talk 19:17, 28 May 2016 (UTC)

Discussion of A8

I think proposal of A8 is looking good, and applaud EEng's edit to concentrate further discussion in this area. I'll kick it off with a couple of comments:

• Certain topics may benefit from a mixed approach...

The use of American football is an excellent example (I would disagree with a previous statement almost exclusively of interest to Americans since the topic is marketed in the UK, and probably in a number of other countries as well).

However, the guideline on mixed approach could include another example, where the primary unit is SI. I couldn't immediately think of a good example. The nearest I could come up with is one I mentioned earlier, main sequence, where the (non-SI) solar mass unit is reasonably explained in the intro, and thereafter only uses the symbol M_☉, which (like the mass of the earth) is pretty much impossible to express in kilograms/metric tonnes or any other unit that could sensibly provide any sense of scale. M_☉ definitely can only be described as a MegaShitload unit.

I'll try and find an SI-based example, but feel free to chip in. (Pseudo sign Robevans123 (talk) 00:16, 29 May 2016 (UTC) - my later unsigned edit screwed my efforts to keep each bullet separate, so that subsequent comments can be easily added)

A possible alternative to the American football article might be Flight level where flight levels are described in feet only for the most part - it's certainly an article with worldwide interest although the number of visits is lower than for American football, but not so prone to seasonal variations. See comparison from Tool Labs for details. Interestingly, (from reading Metrication in the United States), many countries used metric values up until the end of WW II - rather unusual to have a standard switch from metric to USC units. BTW I also found that the US Navy still use kiloyards... Robevans123 (talk) 06:49, 29 May 2016 (UTC)

• Certain topics will not benefit from any conversions or sense of scale

A new item to add to the guidelines. There are some articles where the units are so large or small that it is impossible to provide any sense of scale, and any conversion would be inappropriate, for example Ionizing radiation which uses the electronvolt (eV) extensively. No conversion to any unit of energy (joules, calories, etc) that we can relate to would be useful. The electronvolt is a MicroShitload.

Proposed wording of bullet:

• Certain topics dealing with units of the very large or very small are beyond any sensible conversion and any conversion would be detrimental to the article, for example, Ionizing radiation. Just check the unit is spelt out in full and wikilinked on first usage.

-- — Preceding unsigned comment added by Robevans123 (talk • contribs)

This proposed wording is too vague. There are cases relating to ionising radiation (e.g. converting grays to rads or becquerels to curies) where you might want to offer a conversion. Moreover, there are cases at the "very small" end (e.g. instantaneous luminosity of a particle collider in nb^-1s^-1 or cm^-2s^-1) and at the very large end (e.g. AU to kilometres, megametres, gigametres, or ly to pc) where conversions might be desirable for various reasons.

There are obvious examples, I think, of where a conversion from SI would be useless. Converting the Earth's mass from kilograms to pounds, stones, hundredweights, etc. would be one such example, as I gave above. Archon 2488 (talk) 00:48, 29 May 2016 (UTC)

Yeah, I agree Re123's text ain't so good. I think this is another aspect of the most-cases-where-no-conversion-is-appropriate-are-science-topics thing, other facets of which are already given in A8's drug/visible light bullet, and sense-of-scale semiconductor/assay/giant star bullet. I think that within these three there's a simple principle struggling to get out -- we just haven't found it. I think it would help if "we" (not me -- I'll be traveling for a few days) could exhibit actual passages from e.g. ionizing radiation that should have neither conventional conversions nor a "sense of scale" thingamajig. From those maybe we can find a common theme. EEng 02:24, 29 May 2016 (UTC)

Actually, I think we've already found it. Only convert into units that people in the English-speaking world might actually find useful in the context described. IOW, we don't convert into "unknown or obsolete" units or units and only convert "where English-speaking countries use different units for the same quantity". So far as I can tell this already covers scientific issues well enough. If there's a scientific topic where conversions are useful to the reader, then we should convert. But we shouldn't convert to units that are not likely to be useful to the reader. We might add the words "this is likely to be common in scientific fields" to the "unknown or obsolete" point if we feel the need to specifically mention science, but I think the point is wider. Similarly, there is surely also a sensible principle that we only provide a "sense of scale" comparison if it's useful to the reader and contextually appropriate.

There used to be a point in here that advised using units appropriate to the topic subject, contrasting something relatively general interest (something like Sun) where one might need to use common real-world units with something relatively technical and niche (I think it was Black hole evaporation) where it's fine to only use the technical units used in the fields.

Beyond that, don't convert repetitiously or in a way that actively disrupts the text. That covers "text dense with measurements", the American football example and the four-minute mile example. Kahastok talk 09:56, 29 May 2016 (UTC)

I mostly agree with Kahastok here. The MOS guideline needs to allow editors working on such a topic to use their discretion to decide which, if any, conversions are helpful. My main concern with what is proposed directly above is that we should not broadly declare ionising radiation as a topic where conversions and sense-of-scale equivalences are not relevant (disclosure: I know orders of magnitude more about ionising radiation than I do about American football, and I don't really have a horse in the race where the latter is concerned).

For example, if you're talking about an exceptionally energetic cosmic ray event, it might be helpful to point out that we're talking joules of energy (i.e. it is so energetic that it's of that order of magnitude), whereas in most cases there would be little point in converting eV to J. You'd just say that the unit used is eV, with a link to the article and perhaps the conversion to SI (1 eV ~ 160 zJ) on first use. Other comparisons (e.g. to the LHC collision energy, or to diagnostic or therapeutic X-ray energies) might be helpful depending on context, since these are the areas where eV are most commonly used.

Quantities that are nominal or defined might benefit from a conversion-or-equivalence on first use (i.e. no repetitious conversion), but on no account should we ever talk about the 247-acre array (this point is basically covered by the milligrams-to-ounces example, I think).

The concerns that were brought up above (SI units being deprecated or gigaseconds vs. years) are unlikely to ever constitute a problem in article space, so I continue to feel justified in "airily dismissing" them. Should I be wrong about that, we can always discuss later, but I would bet my life savings that it won't happen. MOSNUM should focus on practical concerns exclusively. Archon 2488 (talk) 11:44, 29 May 2016 (UTC)

I am happy to ignore deprecated or unknown SI units (and strangely you keep ignoring the "unknown" part of that), including gigaseconds, if you are happy with the principle that these rules should apply to all units symmetrically, with no required conversions to SI in those circumstances - wherever they arise - where those conversions are not useful to the reader.

Yes, I've brought units like gigaseconds and kilodays up before, because they serve a useful purpose. When people argue that SI should have some really special status, that we should always convert to it, that we should always use it in general articles - and that happens an awful lot - they are a useful reminder that SI is not always appropriate. That we have to work with, not against, a real world that does not use SI alone and that we always have to consider context. When you or anyone else advocates pure SI, or required conversion to SI, they are advocating kiloseconds, megaseconds, gigaseconds and so on whether they mean to or not.

I maintain that it is a statement of the obvious that if we were required to include a conversion to SI, then that requirement would necessarily include units of time. But I also note that I do not believe this is the effect of the proposal. Kahastok talk 12:20, 29 May 2016 (UTC)

Thanks @Archon 2488 and EEng:! But say what you mean - don't try to sugar coat the 100 mg pill! It was badly worded and overlapping somewhat. It was late at night, blood sugar level was low, seemed useful at the time, and unusually I made a slip (Freudian?) in omitting to sign the article...

It was certainly not meant as guideline that ionising radiation in general was off-limits for useful conversions, just that the article Ionizing radiation was a good example (and this is what I missed out in the bullet) of the shear pointlessness of trying to convert (either into other units or to give a sense of scale) electronVolt values in the 10-33 eV range. The article usefully uses conversions of other quantities later on (and even gets the banana equivalent dose in).

These energy comparisons give a useful range of typical values. I look forward to comparing the designed proton collision energy at the Large Hadron Collider as roughly equivalent to the kinetic energy of 14 flying mosquitos (fM). -;) Robevans123 (talk) 13:01, 29 May 2016 (UTC)

Re. deprecated and unknown: my position is that A) no SI unit has ever AFAIK been deprecated; if and when that happens we will certainly have something to discuss here, but I consider such an eventuality so far-fetched in the short term that there is no point considering it now; B) you've not provided a context in which SI is "unknown" (that's setting the bar extremely high – I can think of no case where SI has a unit that is as obscure as the furlong, let alone the pica, the gill, the grain, the scruple, the troy pound, etc.) so I'm not sure what you're getting at. SI has only one unit per physical dimension, and to the best of my knowledge none of them is obsolete or unknown. If you're saying that (for example) the conversion of megaparsecs to SI would be superfluous since SI is rarely used at such a scale, then fair enough, but "unknown" is too strong for the simple reason that if you did give the distance in zettametres or metres in scientific notation, people would recognise what it meant (I accept that whether it would be useful in said context is a different question); if you gave it in a unit that I would call effectively unknown, such as the pica, the vast majority of people probably would have no idea that it's a typographical unit which would never ordinarily be used in astrophysics. You don't need to call my position "strange"; you could just ask me to explain it more.

Expanding on this: my "(more or less) always convert to SI" position was shorthand for something more nuanced, which I considered too obvious to need to spell out. This is why I say I am a pragmatist rather than a literalist about what the MOS should be. Using hectares instead of hectometres squared is fine, as with litres and decimetres cubed, or tonnes and megagrams. In each of those cases, the formally equivalent SI term has a more commonly used synonym which is officially accepted by the BIPM, and providing the equivalent SI expression every time (e.g. glossing "15 mL" as "15 cm³") is obviously excessive. So far, so good. We do not need to convert litres per 100 kilometres to the more "orthodox SI" decimetres cubed per megametre.

The time units, as you have correctly if somewhat pedantically identified, are a thornier case. The BIPM accepts minutes, hours, and days as units that may be used with SI, but not weeks, months, or years. Above, I speculated as to why this might be (I don't actually know, and in any case it's well beyond the scope of this discussion). Since timekeeping standards have relatively little to do with the BIPM and SI beyond using the SI second as their base, however, this is an angels-on-pinheads matter; the number of days in a year comes down to astronomy, not a human-defined system of measurements. I consider it almost inconceivable that any editor in article space is going to be so confused by this that they will insist that the year is not an SI unit, or that they will actually object to an article referring to the duration between June 15 and August 15 as "two months". So, adding these minor caveats to my position would simply remove the non-problem. Archon 2488 (talk) 14:05, 29 May 2016 (UTC)

If you asked a man on the street in any country you choose to name how many metres were in a zettametre, how many do you think would know? I wouldn't be surprised if not one in ten thousand got it correct. Even if you restricted it to asking Physics graduates, I'd still bet on its being a very small minority. Less obscure than the furlong or the pica? Maybe if you're in Russia or China, but in Britain and America I don't believe that for a moment.

If you wrote 100,000 lightyears (0.95 Zm), how many would know that "Zm" meant "zettametre", even linguistically? Again, I don't for a moment believe it's a large number. By "unknown", that doesn't mean unknown to people who have studied the BIPM standards in detail. It means unknown to the reader, most of whom have never studied Physics. The zettametre is by any even vaguely sensible standard an unknown unit.

I maintain that all units should be treated in the same way, whether they are SI or not. I note that this is the current proposal, which does not imply any special treatment for SI. This does not mean that conversions to SI will not in practice be more common - they almost certainly will be - only that in a given set of circumstances the decision as to whether to convert to a given unit should not depend on whether the unit in question is SI or not. Perhaps it would help if you could give a circumstance in which your notion that SI should be treated somehow specially would be different from the situation where we treat all units symmetrically? The above reads to me like you're saying that SI should be treated specially except in every circumstance in which that would mean treating it specially. Kahastok talk 20:59, 29 May 2016 (UTC)

That is an objection to a specific use of an SI prefix, not an SI unit per se. If the prefix "zetta" is not felt to be of utility, one is free to use metres in scientific notation instead (as I said in my original comment, and to which point you did not respond). In any case, SI prefixes are merely a shorthand for orders of magnitude, so it does not make sense to treat each prefixed unit as a separate unit in isolation.

The use of metres in scientific notation is not remotely uncommon in scientific contexts; indeed it is already what several relevant Wikipedia articles such as this one already do. I object to being patronised and dismissed for defending what is already done in practice, and I reject any suggestion that the use of metres in astrophysics is so unknown that it is in any sense comparable to furlongs or picas. Moreover, you have still not provided an example of when an SI unit is "unknown" (the tesla? Nope. The farad? Nope. The joule? Nope. Continue until you can answer "yes" and we're talking). Whether an editor chooses to provide a conversion to the prefixed SI unit or the un-prefixed unit in scientific notation is irrelevant to the point that I'm making.

Regarding the proposal, my concern here is that language about "deprecated", "unknown", or "obsolete" SI units should not appear, since I am not convinced that it is compatible with NPOV. As a simple, objective fact, SI units are not comparable to legacy units like the foot or "jargon" units like the megaparsec, because this is the consensus of every metrology organisation in the world, which should not be ignored. Ultimately, they are the authority on this, and Wikipedia is not. Wikipedia should respect the consensus of metrology organisations for the same reason that it respects the consensus of climatology organisations; to do otherwise is not NPOV.

The other point (exceptions to necessary SI conversion): I am not sure whether this even needs to be codified in MOSNUM, but the only exceptions I mentioned were where there are "synonyms" for SI that are officially accepted (the litre, hectare, etc.), and time units. OTOH, I cannot say that I am amused by the prospect of allowing a plethora of legacy units without conversion in certain topics simply because they have been sluggish in adopting SI (such as aviation) – this is what I was driving at. I am opposed to some misguided egalitarianism of units that disregards historical context, treating legacy units and modern units as equivalent when the science of measurement and reputable metrology organisations say that they are not. I realise that I am unlikely to persuade others of this, but I do not see that as NPOV. Archon 2488 (talk) 22:39, 29 May 2016 (UTC)

Ah, so you're going for no true Scotsman then? You don't like the counterexamples given so you discount them and ask for more.

It is not neutral to systematically prefer one POV over units over another, much as you might prefer that it is. We work in the real world, not in an idealised world. You refer to "legacy units" but these are units that are used by real people - yes, including real scientists in some fields - day to day in the modern world. I find it difficult to see how it could possibly be considered neutral to push a given set of units in contexts in which they are not used for ideological reasons.

That said, I note with interest that you do not give any circumstance in which your your notion that SI should be treated somehow specially would be different from the situation where we treat all units symmetrically, as I akked previously. Kahastok talk 09:02, 30 May 2016 (UTC)

"It is not neutral to systematically prefer as more legitimate a PhD granted by Cambridge to one granted by Patriot Bible University". "It is not neutral to systematically prefer astronomy over astrology." There are cases where this false egalitarianism, treating cases as equal based on superficial characteristics, will let you down, and it will not lead to a NPOV. I do not accept that a POV on units of measurement formed by denying any special status to all the world authorities on measurement and neglecting the content of the science of measurement is neutral, nor do I need to accept that. What you are pushing is as least as much a POV as anything else that has been proposed here.

I gave a perfectly good rebuttal to your example, which means that I did not commit the fallacy you describe. My point is that you cannot name a physical dimension for which the appropriate SI unit is deprecated, obsolete, unknown, etc. Pointing out that most people do not know how to use large SI prefixes, while correct, does not address this point, and it does not mean that I have committed the No True Scotsman fallacy. In other words, there is no case I know of where no conversion you could provide to SI would be meaningful. To reiterate, my concern here was that none of this language should appear in the proposal; since at present it does not, we don't have too much to discuss here.

I gave the specific example of aviation, since that has been much discussed here. I reiterate my discomfort with allowing in any context the mass use of legacy units without conversion; I believe, at the very least, that the bar (if you will forgive the pun) here needs to be much higher than for justifying SI-only in a science article (or, to put the shoe on the other foot, for justifying that all the heights of trees in a botany article need to be converted to feet and inches). I don't think this is a crazy perspective, but I concede that it might be hard to codify at the level of the MOS. The present text "[c]ertain topic areas may benefit from a mixed approach" is a bit vague, and it leaves perhaps too much power in the hands of editors. But I I could be wrong about that, and until and unless that causes a problem in articles, I don't strongly object to it.

To come to some sort of conclusion: I do not strongly object to A8 as it stands, but I did have other peripheral concerns, which probably cannot be further addressed here. Archon 2488 (talk) 11:25, 30 May 2016 (UTC)

I don't think anyone's saying that conversions to metric shouldn't be common, even the default, applying most of the time, since in most fields they are standard. The only question is whether to give them some kind of special status when they aren't standard or routinely used. As I say, you seem to be arguing that they should be, except for every time the situation arises. I don't accept that. They shouldn't be treated specially. It's not neutral or beneficial to require any conversion - to metric or to non-metric - when they aren't useful to the reader. But that is not to say - has never been to say - that conversions to metric units are not more likely to be useful to the reader in many fields than conversions to non-metric units.

In terms of "[c]ertain topic areas may benefit from a mixed approach", my argument would be that if you want to not convert - like any other exception - you need to be able to say why. Same as when we had people arguing that articles on Ukrainian cities should be miles first: why? If you can correctly answer that based on the rules, fine. If you can't, you have to convert. Kahastok talk 12:27, 30 May 2016 (UTC)

• I'll be leaving for the airport in a few hours so this may be my last post here until Thursday. Let me strongly suggest that discussion goes best when posts offer concrete proposals (even if rough, tentative, or incomplete) for changes to the guideline text and examples. EEng 15:16, 29 May 2016 (UTC)

Propose adopting A8

I propose that Proposal A8 be incorporated into WP:MOSNUM. Kahastok talk 09:03, 30 May 2016 (UTC)

• Support as this seems sensible advice as to when to provide conversions and when not to. Kahastok talk 09:03, 30 May 2016 (UTC)
• Support I was gonna suggest waiting for more discussion and adjustment, but on reconsideration I think this is good enough to go in as is, though I'd be very surprised if more discussion and adjustment won't be needed on certain details. If there's significant dissent, however, we should suspend !voting and resume discussion on this page. EEng 06:05, 2 June 2016 (UTC)
• Support A reasonable guidance on when to convert and not. Like all guidelines, apply commonsense and editorial discretion. Robevans123 (talk) 07:40, 2 June 2016 (UTC)
• Support - much more well-thougt out than anything I could have proposed. FunkMonk (talk) 12:38, 2 June 2016 (UTC)

Much more well-typd out, too! EEng 13:17, 2 June 2016 (UTC)

• Support – I don't see much reason to be concerned with the wording at present; if there are cases where it proves problematic in practice, then of course we can always discuss again. Archon 2488 (talk) 18:21, 2 June 2016 (UTC)
• Support – has adequately addressed the concerns raised in the OP; caveats above could have gone without saying. Not that I would dream of accusing anyone here of verbosity.—Odysseus1479 00:06, 3 June 2016 (UTC)

Ping! I'm surprised not to have heard at this point from more of the usual suspects, such as Tony1. This would be a large addition, and it doesn't have to be perfect, but still I'd like to hear that others have no serious objections. EEng 18:05, 10 June 2016 (UTC)

• Oppose because of (i) the proposal to end mandatory conversions (the introduction of the word "typically"); and (ii) the removal of the long-standing explicit allowance to avoid gobbledy conversions to British Empire units in scientific articles. Some of A8 is good, but my other issues are:

T1. What are "English-speaking countries"? India? There are more native anglophones in the Phillipines than in New Zealand. Do you mean "majority native English-speaking countries"?

T2. "Where English-speaking countries use different units for the same quantity"—Badly ambiguous.

T3. "will typically be used"—can't we use present indicative throughout? ("are typically used"). This applies also to "should be". Perhaps if absolutely necessary, but straight, simple, consistent grammar is better for the readers.

T4. "do not convert where it would make a common or linked expression awkward"—Why does linking an item make its conversion awkward? No example is provided, either.

T5. Why clutter up text with two non-metric conversions? This is over the top: "Where an imperial unit is not part of the US customary system, or vice-versa – and in particular, where those systems give a single term different definitions – a double conversion may be appropriate: Rosie weighed 80 kilograms (180 lb; 12 st 8 lb) (markup: {{convert|80|kg|lb stlb}}); The car had a fuel economy of 5 L/100 km (47 mpg_‑US; 56 mpg_‑imp) (markup: {{convert|5|L/100km|mpgus mpgimp|abbr=on}})."

T6. What is wrong with "Florida"? Ash covered some 170,000 km² (66,000 sq mi, or about the area of Florida) (Scale comparisons should have concrete meaning for most English-speaking readers, and should not be the closest match from an arbitrary list of candidates.)

T7. There's a MOS breach in "Earth-Sun distance".

T8. "In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases judgment will dictate which, if any, measurements should carry conversions:"—the examples work nicely because the components make a range from low to high, with one conversation at either end. It would be nice if this logic was made clearer, or I can bet you editors will start inserting conversions at the start and end of non-ranged lists.

Tony (talk) 04:05, 11 June 2016 (UTC)

Well, that's the last time I ping you! But let's see if I can talk you down off the ledge.

Re T1, T2, T4, T5. This stuff is all verbatim from the current guideline, so can we take up those issues later? (And there is indeed an example for your point 4.)

Re T3, T7. Can you just fix these? Please create a new Use version A9, below.

Re T6. Please be assured I have nothing against Florida itself. (Well, actually I do, but it's not relevant here.) My point is this: Florida has an area of 65758 sq. miles, Missouri 69707, Wisconsin 65496. Since the ash covered 66000 sq mi, we compare it to Florida, but if it were 65000 we'd be sayig Wisconsin, or if it was 70000 we'd say Missouri. No one but some geography-memorizing highschool geek (and an American one, at that) would be able to appreciate the difference; it's a kind of coded overprecision. Even for Americans, states other than Alaska, Texas, and maybe Californa (big!) and Rhode Island (small!) have very little meaning along these lines, and I can only imagine how helpful such comparisons are to a Brit -- about as helpful as "about the size of York" would be to me.

That leaves your points (i), (ii), and T8. Can you be more of your usual precise self in describing the problems you see, and what you'd like to be different? (And by "British Empire units", do you really mean US Customary?)

EEng 05:11, 11 June 2016 (UTC)

• Oppose pending resolution of large number of suggested improvements. See above (my list, Tony1's, and prior comments). This is on the right track, but it's far too early for a forced !vote. This is not a parliament/congress, and we should get it as good as possible the first time, not try to re-legislate it later.  — SMcCandlish ☺ ☏ ¢ ≽^ʌⱷ҅_ᴥⱷ^ʌ≼  09:22, 11 June 2016 (UTC)

I've moved your list from an earlier section to just below here, to keep discussion more linear. I've also labeled both your and Tony's points (T1, T2, etc.) for ease of discussion. (I realize that upsets the indenting a bit.) I hope that's not objectionable. EEng 12:20, 11 June 2016 (UTC)

• Still needs work. I agree with the general idea behind this – give more detailed advice that makes better sense in more contexts. But I have several particular objections, corrections, and suggestions:

S1. "United Consolidated Amalgamated Intergalactic GigaPharma Ltd." is ridiculously verbose, and violates MoS anyway (we don't add "Ltd", "Co.", "Inc.", etc. after company names). Either use a real example or a fake one, but make it concise.

S2. "not its 100 mg (1+9⁄16 gr) tablets and definitely not its 100 mg (0.00353 oz) tablets" – remove "definitely"; it implies that the first "not" isn't "definite" and is really just a "maybe", and further implies that any "not"/"do not"/"do"/etc. in MoS (or any other guidelines) is really a "maybe" if not given with "definitely".

S3. "Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in)." – This is pointless and wrongheaded, and we would never do this. It begs to have the missing values filled in, and if the conversion is useful for the first and last case, it will be useful for all these cases. In reality, such instruments would almost certainly not have both units on them. What is probably desired here is that people get an sense of the total range, in units familiar to them, and that the specific models be specified in the units actually used on them: Popular gauges are in the 6.5–45 mm (0.256–1.77 in) range, most commonly: 6.5 mm, 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm. Furthermore, if the instrument in question really did use both units conventionally, it would not be likely to use "0.256 mm", but the closest fraction, and probably divisible by 2 (often by 4 or even 8), and in standardized patterns. So, in such a case we would use the actual fractional inches shown on the gauge, and provide it for each named gauge. If the gauges conventionally only provide one unit not both, we would just specify the one, and provide conversion for the range. We needn't say all that here, just get the example to make sense in the context of actual articles written about actual gauges.

S4. "In some circumstances secondary" needs a comma between "circumstances" and "secondary".

S5. "if not allowable under WP:CALC" – Give the full location, WP:No original research#Routine calculations, don't use shortcuts in actual guideline wording, since they are meaningless to people who do not already possess "WP:EXPERTISE" (well, we can get away with "WP:" for "Wikipedia:" in the running prose, but in hatnotes we even spell that part out).

S6. All of this example code needs to use non-breaking spaces between the values and the units.

S7. Piped links like "radius of the sun" should be given as <code>[[Solar radius|radius of the sun]] not [[solar radius|radius of the sun]]. While it is not required, the completely conventional capitalization of the real article name at the start of the piped link is part of how we insta-recognize one of these as a piped link in a small fraction of a second when looking at code, without having to parse it visually in detail.

S8. We should add a recommendation (unless it's already present in other text in this section) to not provide conversions to unusual or obsolete units. Weight weight should not be given a conversion to Stone (unit) for much of anything; Britons understand this unit when it is applicable (e.g. to British athletes), but they also understand the kg version, so there's no need for the stone version, and it should not be given for the weight of a motorcycle or a donkey. Similarly, Hand (unit) should never be provided for anything but livestock conventionally measured with this unit.

S9. "Visible light is usually defined as having wavelengths in the 400–700 nm range" should be Visible light is usually defined as having wavelengths in the 400–700 nanometer range. Other examples also need to illustrate that an unit that is not an everyday one for average people (ft, kg, etc.) should be spelled out in full and linked on first occurrence. Remember that people come to these sections

S10. "star of radius 257 million kilometres" is awkward nerdspeak; use plain English: "star with a radius of 257 million kilometres".

S11. Agree with above comment that the section on mixed usage should also provide an SI example, so people don't think this is some kind of "be gentle with the stupid Americans" thing. I would suggest pool (pocket billiards) as a good example, it actually uses mixed systems of units. Tables are given in foot approximations regardless of location (e.g. "a 9 by 4.5 foot playing surface"), though often given in cm or mm in official pro competition specifications, cue weights are given in ounces or grams depending on location, ball sizes are given in inches or mm depending on location, and cue tip widths are always given in mm, even in the US. A complex example, e.g. for three-cushion billiards, can be cribbed from that article and/or from details at billiard table, billiard ball, and cue stick.

S12. Also agree with above comment: "There are some articles where the units are so large or small that it is impossible to provide any sense of scale, and any conversion would be inappropriate".

I have no pored over all the comments, and might well concur with others; I mostly just read version 8 and observed where I saw it was lacking. (And don't be discouraged; a rewrite of this level of detail and complexity takes work, and many editors from different editing spheres will notices different kinds of gaps, loopholes, etc.)

 — SMcCandlish ☺ ☏ ¢ ≽^ʌⱷ҅_ᴥⱷ^ʌ≼  09:20, 11 June 2016 (UTC)

My comments on SM's points:

Re S1. I know you're a Scotsman but still you may vaguely recall what a joke is. MOS need not adhere to MOS, and if anyone points to this example to bolster his side in some style argument, we can simply issue an instant WP:CIR block.

Re S2. See MOS:DECADE.

Re S6. I figured I'd add the nbsps and stuff when (if) this actually goes into the guideline.

EEng 12:51, 11 June 2016 (UTC)

Proposal A9

I have an important deadline in two weeks so I really shouldn't be spending time on this, no matter how much I enjoy the company of my esteemed fellow editors. I'm even going to unwatch for that time -- let's see how long I can stay away. I wonder if SMcCandlish and Tony1 can integrate their thoughts and comments into Version A9 (here), to the extent they think such changes won't be controversial. (This has been a pretty chill discussion, so be bold.) Remaining, less easy, points can then be hashed out further down. Good luck, my friends. EEng 12:51, 11 June 2016 (UTC)

Where English-speaking countries use different units for the same quantity, the "primary" quantity will typically be followed by a conversion in parentheses. Generally, conversions to and from metric units and US or imperial units should be provided:

  •   the Mississippi River is 2,320 miles (3,734 km) long (American topic)

  •   the Murray River is 2,508 kilometres (1,558 mi) long (Australian topic)

• However, do not convert where it would make a common or linked expression awkward (The four-minute mile).
• In some circumstances secondary units are unknown or obsolete in the topic area, and of little or no value to the reader:

  •   United Consolidated Amalgamated Intergalactic GigaPharma Ltd. withdrew its 100 mg tablets not its 100 mg (1+9⁄16 gr) tablets and definitely not its 100 mg (0.00353 oz) tablets

  •   Visible light is usually defined as having wavelengths in the 400–700 nm range not the 400–700 nm (15.8–27.6 × 10^-6 in) range

• In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases judgment will dictate which, if any, measurements should carry conversions:

  •   Popular gauges are 6.5 mm (​0.256 in), 30 mm (1.18 in), and 45 mm (1.77 in).

but Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in).

• Certain topics may benefit from a mixed approach e.g. American football:

  •   The field is rectangular, 120 yards (110 m) long and 53+1⁄3 yards (48.8 m) wide, with goal lines marked 10 yards (9.1 m) inward from each end ...

Note: This section discusses movements of the ball in units of yards (0.91 m), as is standard in the sport. On a kickoff, the ball is placed at the 35-yard line of the kicking team (the 40-yard line in high school play). If the offense advances ten or more yards in the four plays, they are awarded a new set of four plays. If they fail to advance ten yards, the ball is turned over to the defense ...

• Where an imperial unit is not part of the US customary system, or vice-versa – and in particular, where those systems give a single term different definitions – a double conversion may be appropriate: Rosie weighed 80 kilograms (180 lb; 12 st 8 lb) (markup: {{convert|80|kg|lb stlb}}); The car had a fuel economy of 5 L/100 km (47 mpg_‑US; 56 mpg_‑imp) (markup: {{convert|5|L/100km|mpgus mpgimp|abbr=on}}).
• In some cases, it may be helpful to provide a sense of scale instead of, or in addition to, a conventional conversion (though a source may be needed for such comparisons, if not allowable under WP:CALC):

  •   fabrication of semiconductor devices as small as 14 nm (about 63 silicon-atom diameters)

  •   precise assays are possible on samples as small as 0.1 ml (about the size of a pinhead)

  •   a giant star of radius 257 million kilometres (160 million miles, about 370 times the radius of the sun and 1.72 times the mean Earth-Sun distance)

but not

  •   Ash covered some 170,000 km² (66,000 sq mi, or about the area of Florida) (Scale comparisons should have concrete meaning for most English-speaking readers, and should not be the closest match from an arbitrary list of candidates.)

• Converted quantity values should use a level of precision similar [etc etc]

Proposal B1

I disagree that we need to change the guidance, the sub point already clarifies what is meant by this. But if we must 'clarify' the guidance, let's go with this

Where English-speaking countries use different units for the same quantity, follow the "primary" quantity with a conversion in parentheses: the Mississippi River is 2,320 miles (3,734 km) long; the Murray River is 2,508 kilometres (1,558 mi) long. In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so is not usually required, but can sometimes be helpful. If unsure, discuss on the article's talk page.

• • When units are part of the subject of a topic – nautical miles in articles about the history of nautical law (5 nautical miles), SI units in scientific articles (a 600-kilometer asteroid), yards in articles about American football – it can be excessive to provide conversions every time a unit occurs. It might be best to note that this topic will use the units (possibly giving the conversion factor to another familiar unit in a parenthetical note or a footnote), and link the first occurrence of each unit but not give a conversion every time it occurs.
  • In science-related articles, instead of conversions to imperial units, it may be helpful to provide a sense of scale instead. For example, Aldebaran is an orange giant star with a radius of 61 million kilometres (44 times the radius of the sun) or a 14-nm design (about the size of 63 silicon atoms).

Headbomb {talk / contribs / physics / books} 13:36, 22 May 2016 (UTC)

The point isn't just that we need to clarify further, but mainly that exclusion of conversions should be the exception, not the rule. FunkMonk (talk) 13:41, 22 May 2016 (UTC)

Systematic conversions like "a dissipation power of 100 W (341.2 BTU/h)" or "a 20 mg (0.00071 oz) dose of fluoxetine" are nothing but clutter and utterly pointless. Conversions should be a matter of editorial judgment, and usually left out unless there's a reason to include them. The height of a plant? Probably should have a conversion because that's an every day thing. The power output of a supernovae? The surface gravity of Ceres? The mass of an electron? Conversions not needed. Headbomb {talk / contribs / physics / books} 14:14, 22 May 2016 (UTC)

Which is exactly why it should be the exception ("not needed in highly technical sections"), not the rule. A huge bulk of our "science-related articles" are about "everyday things", including animals, plants, technology, and tonnes of other subjects. Wikipedia is not written for experts. FunkMonk (talk) 14:18, 22 May 2016 (UTC)

The opening sentence of Proposal B1 reads "Where English-speaking countries use different units for the same quantity..." - please can we see some examples of where America (for example) uses BTU/h for power output? Or 10,000ths of a ounce for medical dosage? Or slugs for the mass of meteors? Or supernovae output in anything but Foes (a non-SI unit...)? Or electron mass - anything apart from kg (to a very small magnitude), MeV/c2, or atomic mass units?

However, I do like the note on providing a sense of scale (but if kilometres are good, then why not miles as well?).

And if we're going to talk about Ceres:

• "Its diameter is approximately 945 kilometers (587 miles)" - from the article
• "This image was taken by the Dawn spacecraft on 2 May 2015, during a "rotation characterization" orbit, 13,642 kilometres (8,477 mi) above the surface of Ceres." - from the article

Unfortunately, mass, surface temperature, and gravity are only given in the infobox (without conversion - but the gravity is given in m/s² and standard gravities). Looking at Vesta 4, I note that most crater dimensions are given kilometres and miles and surface temperatures are given in degrees centigrade Celsius, not Kelvin. So it seems that asteroids and dwarf planets use a number of conversions to about the right level (although they could possibly be improved by a bit more conversion), but they are certainly not cluttered by the conversions that are present.

And in checking on drug doses I came across the General considerations section in the Pharmacology WikiProject's Style Guide, which explained why drug dosages are not commonly given in Wikipedia articles, and also stated

Finally it is important to keep in mind that we are writing a general encyclopedia, intended to be read by the lay public so it is important to make technical material as accessible as possible to a wide audience but at the same time, not reducing the value of the article to more technical readers including medical doctors, pharmacists, and scientists.

Which I think neatly summarises what we should be trying to achieve in any recommendations on the use, or not, of conversions in the style guide... Robevans123 (talk) 20:45, 22 May 2016 (UTC)

To answer your questions: BTU/h would be a standard unit in some US industries, for example in measuring the energy consumption of radiators. It would not be common in a scientific context, which is what we are discussing here. Nor would the use of decimal avoirdupois ounces. The choice of units used in science is (in most fields) quite minimalist; when nonstandard units are used on WP, they should always be converted to SI, since even a scientifically literate person cannot be expected to understand the minutiae of obscure units that do not exist outside of certain fields (astrophysics is perhaps the worst offender in this regard).

I am opposed to opening the door too much to "conversion proliferation" because I don't see where it ends; converting asteroid masses to pounds or stones, or their dimensions to statute or nautical miles, or to something else (furlongs? cables?), is just not very purposeful. Fact is that all those units would be more or less equally unlikely to appear in a reputable scientific source. There are lots of nonstandard units which might be used to give such dimensions, but that does not mean that WP ought to provide those dimensions in such units.

I don't think that "highly technical" can be the guideline either. For one thing, that is vague. For another, there are many non-highly-technical scientific subject areas where the use of non-SI units would be quite unusual, and even some highly technical areas where non-SI units are common.

So to reiterate: I think that the default guideline in any science-related article should be to default to SI+friends, with optional conversions to any other units which might be used by reputable scientific sources in the relevant field (I am cautious about talking of "the rule" and "the exception" since I do not know how often such an "option" would be exercised). In practice, this is not vastly different from what happens in many science articles at present. Archon 2488 (talk) 15:20, 27 May 2016 (UTC)

Phantom clutter

What I find problematic with the above is the following.

In text dense with measurements, conversion of every measurement may add clutter to little benefit. In such cases judgment will dictate which, if any, measurements should carry conversions:

  •   Popular gauges are 6.5 mm (​0.256 in), 30 mm (1.18 in), and 45 mm (1.77 in).

but Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in).

It appears as if this was deliberately contrived to look awful. They say "Never attribute to malice that which is adequately explained by stupidity." though. (I don't mean to insult anyone, this is just the way the phrase goes.) Seriously, though, who would write this way? It's horrible and should not be encouraged by inclusion in the MOS. A writer with an ounce (28.4 g ... {jokes}) of style would write

"Popular gauges are 6.5, 30 and 45 mm (0.256, 1.18 and 1.77 in)."

not this hideous

"Popular gauges are 6.5 mm (​0.256 in), 30 mm (1.18 in), and 45 mm (1.77 in).".

Likewise,

"Popular gauges are 6.5 mm (​0.256 in), 9 mm, 12 mm, 16.5 mm, 20 mm, 25 mm, 30 mm, and 45 mm (1.77 in)."

should become

"Popular gauges are 6.5, 9, 12, 16.5, 20, 25, 30 and 45 mm (​0.256–1.77 in).".

However, now that this is rewritten more sanely, we can see that we're not going to get anything as ridiculous as

"Popular gauges are 6.5 mm (0.256 in), 9 mm (0.354 in), 12 mm (0.472 in), 16.5 mm (0.650 in), 20 mm (0.787 in), 25 mm (0.984 in), 30 mm (1.18 in) and 45 mm (1.77 in)"

anyway. Instead, this would become

"Popular gauges are 6.5, 9, 12, 16.5, 20, 25, 30 and 45 mm (0.256, 0.354, 0.472, 0.650, 0.787, 0.984, 1.18 and 1.77 in)",

which, of course, is still very ugly but not nearly as bad.
On the other hand, though, what's the use of such a sentence anyway? If we've got a list as long as this, the best way to deal with it would be to put the values in a table and then you'll not have to worry about the clutter at all. No, we don't want to add clutter but what's going on here is merely doubling the clutter already there. If we don't fancy clutter, don't have it in the first place.
I get the general thrust of what is being discussed here but I think the example is terrible. Is there even a good example we could use or might it be that, in all such cases, it's merely an artifact of bad style that we end up with long lists of values in prose? Should there ever be text dense with measurements? Jimp 04:28, 4 June 2016 (UTC)

Should time after 24:00 be considered as the next day?

In some situation, people might report an event as happening on a specific date, but it is actually happening on the day after. For instance, a Television program might advertise it is going to be air on May 20, but the actual air date for the program could be May 20 27:30, i.e. May 21 03:30. Should we regularize those time and change the date to the actual date in 24 hour system, or should we follow the date given by the subject of the article? In MOS:ANIME the regularization is recommended, is there any other manual of style on wikipedia that talk about this matter, and should we add this to this date and time MOS? C933103 (talk) 13:06, 20 May 2016 (UTC)

I'm familiar with "unnormalized" times such as you describe, but I doubt most readers are. I would suggest normalizing to (in this example) May 21 03:30. Doing so doesn't change the meaning in any way (May 20 27:30 is the day after i.e. May 21, just expressed in a disguised way) and is more accessible to readers. EEng 16:02, 20 May 2016 (UTC)

Most of the days I've come across have only 24 hours in them. Just ask Gene. Martinevans123 (talk) 23:10, 21 May 2016 (UTC)

Oh yeah? What about leap seconds, know-it-all? EEng 00:40, 22 May 2016 (UTC)

Now, they are hardly entire hours, are they? Martinevans123 (talk) 08:54, 22 May 2016 (UTC)

Timezone usage for places where sovereignty is conflicted

How to determine "time zone where an event took place" when different party involved in the incident have different opinion about what timezone should be used over the place? For instance, if further conflicts take place in Crimea and the result is still inconclusive, should we use Moscow time (as used by the current Crimean authority that follow Russian regulation) or Ukraine time (as the original Crimean government would use)? Or, if we found an alien body on Senkaku/Diaoyu Island via satellite, should we use Chinese Time or Japanese time to denote the time we discover that body?

On the other hand, how to determine "place at which the event had its most significant effects"? For instance, if North Korea dropped a nuclear bomb near Vladivostok, Russia and killed hundred of thousands people there, but then most of its subsequent fallout spread across much of the China and then threatened the life of billion people in China, then should we use Vladivostok time or Beijing time to record the event's sequence?C933103 (talk) 16:25, 20 May 2016 (UTC)

Your first question is a fascinating one; I don't know the answer. Have you tried discussing this on the article's talk page? (Whatever the answer is, the article should make clear which zone is being used.)

The answer to your second, hypothetical (and let us hope it remains so) question is: it's impossible to make advance rules for all these kinds of things. If it happens, hash it out on the talk page of the article first. If that fails... well then we'll see. (My guess would be you'd give the bombing time in the zone where the bomb exploded, and fallout in the zone of whatever places at which you want to describe its arrival and effects, making clear its "local time" or whatever in each case. Or, if the time-of-day of arrival isn't really important -- and it's not a discrete event anyway -- you might just say, "Within X hours, radiation detectors at Beijing began to register significant blah blah.") EEng 18:31, 20 May 2016 (UTC)

Another alternative, if a detailed timeline is needed, would be to systematically use both times, or give one time and note the offset to the other. Not a huge deal.

On the first point, the most normal rule - particularly if there is no obvious relevance to the dispute in question - is to use the time zone actually used on the ground. For example, consider Korea. Each of the two governments (North and South) considers itself to be the sole legal government of all of Korea. North Korean time is UTC+8.5 (since last August), while South Korean time is UTC+9. When giving start times of events during the 2018 Winter Olympics, we will use South Korean time exclusively. When giving start times of football matches in Pyongyang (e.g. 2018 World Cup Qualifiers), we use North Korean time exclusively. Kahastok talk 18:53, 20 May 2016 (UTC)

Those must be some skinny, skinny football players. EEng 23:37, 20 May 2016 (UTC)

If giving the time in one time system or the other would be seen as taking sides, then the ultimate equality would have to be to use UTC.  Stepho  talk  10:33, 22 May 2016 (UTC)

WTH?

"In science-related articles, however, supplying such conversion is not required unless there is some special reason to do so." So we get US units only in a science article? No way ... I pushed through what was originally SI units with optional conversion to US units in science-based articles, back in about 2007. How on Earth did this morph into the potential for US units only in an article on the Solar System, for example??? Tony (talk) 15:43, 28 May 2016 (UTC)

I don't see how that text suggests you'd use US-units-only in a science article (clearly you'd use SI as primary, and what this says is that you might not need a conversion to US to go with the SI), and I have no idea where it came from, but anyway the current proposal removes it. Can you take a look at A8 (above)? EEng 16:05, 28 May 2016 (UTC)

SI prefixes and symbols "restricted"?

I'm not entirely sure about the phrasing here:

• SI prefixes and symbols, such as giga- (G) and tera- (T), should be restricted to scientific, engineering, and technical uses.

given that most of the world's road signs use SI symbols such as "km" and most of the world's food packaging uses SI symbols such as "g" and "kg", I strongly dispute that the use of SI symbols is, in real life, "restricted to scientific, engineering, and technical uses". What I suspect this might have been trying to say was (in line with a point I made in a previous discussion) that SI symbols should not be used in a non-SI context. Thus, for example, no "megamiles (Mmi)", "kilopounds (klb)", "megadollars (MUSD)", since these are non-standard notations.

Would it be too bold to propose rewording the bullet along these lines, or have I completely missed something? As it stands, it suggests that every single occurrence of a measurement like "50 km" on Wikipedia is inappropriate, which is absurd. Most such measurements, I would suggest, are not found in technical contexts. I therefore propose rephrasing this as:

• SI prefixes, such as giga- (G) and tera- (T), should be used only in SI expressions, such as 50 km, and not otherwise (e.g. 50 klb).

Archon 2488 (talk) 18:36, 2 June 2016 (UTC)

In context I don't think it's intended to mean that at all. It's not even in the section on units of measure. In context (discussing treatment of large numbers) I think it's a rather over-sweepingly-worded rule that is intended to prevent use of high-magnitude prefixes/symbols such as giga- and tera-, that may not be known to the lay reader, in inappropriate contexts. The same logic would also apply to low-magnitude prefixes/symbols such as nano- or pico-.

So for example, it rejects gigadollars (G$) in favour of "billion dollars", but also gigagrams ("million kilograms") and terajoules ("trillion Joules"). Kahastok talk 19:06, 2 June 2016 (UTC)

Fair enough. Although my point stands inasmuch as the original wording has got to go. Even if it's in a different section, we can't have wording which is so broad that it directly contradicts things that are said elsewhere in the MOS.

I thought we already had language to the effect that only units of an appropriate order of magnitude should be used. If this is all that's meant here, I am not sure what the additional benefit of such a rule could be. Units like picometres or terajoules will be used where they are conventional, and not otherwise; I would dispute that the diameter of an atom should be expressed in "trillionths of a metre" rather than picometres. Anyway, if we're going to say (as I suspect we should) that SI symbols belong with SI/metric units and not elsewhere (with possible additions like "Mya" where that is the conventional notation), then I suspect this bullet might be entirely pointless.

Regarding my original proposal, I now think that it might be better suited to the table in the section on measurements, under "Prefixes", since that is where the other rules about SI prefixes are. Archon 2488 (talk) 19:20, 2 June 2016 (UTC)

The diameter of an atom surely comes well within the range of "scientific, engineering, and technical uses".

I am not aware of any rule restricting units to an appropriate order of magnitude and wonder if that's workable. Difficult to see that the dollar is a useful order of magnitude for the National debt of the United States, but we basically bar all other alternatives. I agree that the wording is overly broad, but the principle I outlined is sound I think. If we are in a genuinely non-technical, non-scientific, non-engineering field I think we should prefer "... billion Joules" to "... gigajoules". Real world example, we should be measuring the distance from Sydney to Perth in thousands of kilometres rather than megametres.

On your proposal, I am sceptical. I agree we shouldn't be inventing such units where they are not conventional - that is surely a more general rule, we should not invent units that don't exist in the real world - but if there is a field where they are conventional, we shouldn't refuse to use them. Kahastok talk 19:57, 2 June 2016 (UTC)

OK, sorry, that was a silly example. A better one would be that large volumes of water in Australia are commonly measured in units such as megalitres and gigalitres (I have no idea whether this counts as "technical"; one could argue that an article on economics such as the US national debt is "technical"). In any case, the rule should surely be to follow real-world practice here, rather than saying broadly "don't use large SI prefixes". I am not sure how often energy units of any sort are used in non-technical contexts, but in any case the real-world practice should be followed. Archon 2488 (talk) 21:08, 2 June 2016 (UTC)

The gas bill is in terajoules. But we never say "gigagrams" because a megagram is always called a tonne. Hawkeye7 (talk) 21:56, 2 June 2016 (UTC)

Indeed, that is another good example – megatonnes and gigatonnes (for example, in measuring explosions and carbon emissions). Archon 2488 (talk) 22:43, 2 June 2016 (UTC)

Perhaps we could get the point across with something like:

• SI prefixes and symbols, such as giga- (G) and tera- (T), should not be used to express magnitude of numbers, except where forming common units of measure in the field discussed.

We could give examples like, they emitted 5 megatonnes of CO2, but Spending rose by G$5 per year.

I think most of the situations where this legitimately arises with large measures - including the desalination plant, the explosive capacity and the carbon emissions - could be characterised as within "scientific, engineering, and technical uses", but that does not resolve issues with the current wording apparently banning kilometres and kilograms and I could accept an argument that that stretches "scientific, engineering, and technical uses" somewhat beyond what is reasonable. As an aside, personally I would have a preference for "billion litres" over "gigalitres" in the article on the desalination plant for clarity. Kahastok talk 18:28, 3 June 2016 (UTC)

I'd say get rid of the phrase entirely. It's only common sense to avoid these larger and smaller less well known prefixes in contexts where they might cause trouble. What are these contexts exactly, though? It doesn't seem that a simple rule could sort things out and "technical" is a bit vague. The rule is likely to cause more confusion than clarity. Just ditch this instruction creep. Jimp 03:25, 4 June 2016 (UTC)

Tempted to agree with you, actually. Surely the default MOS rule should be that such weird nonstandard usage is not allowed; we shouldn't spell out specific cases unless there's evidence that there has been real confusion over this. I don't think I've ever seen notation like "G$" used anywhere on WP. Archon 2488 (talk) 14:21, 6 June 2016 (UTC)

Imperial gallons

Is there ever a reason to include Imperial gallons in the unit conversion when the primary unit is not Imperial? I would think not, but I ask because that's the default behavior of the convert template. Kendall-K1 (talk) 15:01, 10 June 2016 (UTC)

I can't see much use for it in contemporary material, but perhaps in a historical context? LeadSongDog come howl! 16:25, 10 June 2016 (UTC)

For everyday volumes, imperial gallons are still better understood in the UK by older people than litres; for example, although I buy petrol in litres, I only know my expected petrol consumption in miles per (imperial) gallon. Another reason to use them sometimes is to clarify the difference between US and imperial gallons. Peter coxhead (talk) 16:36, 10 June 2016 (UTC)

What got me thinking about this is Plant Bowen, an article about a US power plant, where I just removed conversions to Imperial gallons. Should I have left them in? Kendall-K1 (talk) 16:59, 10 June 2016 (UTC)

I don't think so. Litres suffice in such a case. It simply needs to be made clear that one is talking about American gallons, but that's already done. Imperial gallons should only be used in a context where they make sense, i.e. historical British, Canadian, Australian, &c., usage. There is no reason to include imperial gallons in an American context, as all countries that used imperial gallons as a primary unit now primarily use litres, meaning that non-American readers will be able to understand the given conversion to litres. RGloucester — ☎ 17:12, 10 June 2016 (UTC)

My experience is that although it may be true that all countries that used imperial gallons as a primary unit now primarily use litres it's far from true that non-American readers will be able to understand the given conversion to litres. Editors need to consider the context of the conversion and the set of readers likely to be most interested in the material; readers should come first. But I agree that for a US power plant there's no point in providing a conversion to imperial gallons. Peter coxhead (talk) 09:24, 11 June 2016 (UTC)

WP:DATERANGE again

I just can't let go how much I despise the two-digit abbreviation of end-range calendar years that was introduced into the MOS. There are many problems with it, here are the main ones that come to mind:

• It can easily be confused for something else entirely, especially for ranges ending in years '01–'12. For example, 2010–12 can easily be interpreted as December 2010 instead of a date range of 2010–2012.
• It looks so unprofessional. Saving a measly two digits is not worth giving the appearance of using unnecessary shortcuts/slang in a respectable encyclopedia.
• It doesn't read naturally for years in the 21st century spanning the 2000s decade to 2010 or later. This is mainly because years from 2000–2009 are usually pronounced "two thousand and", while years from 2010—present are usually said as "twenty". So a range such as 2000–16 being read as "two thousand to sixteen" sounds ridiculous. This is especially problematic for anyone having Wikipedia read aloud by a text-to-speech program.
• It's inconsistent, since it is only applicable to years 1000 AD+ and to none of the years in the BC era (why not?), leading to more confusion and unnecessary stylistic asymmetry.

If it's to be kept, I think the only defensible use is in an Infobox that is overloaded with date ranges (but only if it is overloaded), making space more valuable to save. Otherwise it is unprofessional, unnecessary, awkward, and open to misinterpretation and should be abandoned. Crumpled Fire (talk) 07:57, 11 June 2016 (UTC)

I agree. (And the same argument applies to page ranges in citations too.) In almost all circumstances, not abbreviating such ranges has no balancing advantages over the obvious disadvantages. Peter coxhead (talk) 09:09, 11 June 2016 (UTC)

Thank you. I think a most egregious example of a disadvantage is in marriage ranges in the Infobox. Something like "John Smith (m. 2004–12)" is almost entirely ambiguous to anyone unfamiliar with Wikipedia's MOS in regard to whether it is stating that they got married in December 2004, or were married from 2004–2012. Crumpled Fire (talk) 09:20, 11 June 2016 (UTC)

There is no ambiguity, because a range takes a dash (2004–12) but a year-month takes a hyphen (2004-12). Just kidding, I think you're right. It might be a useful shortcut if there weren't so many exceptions. Kendall-K1 (talk) 12:28, 11 June 2016 (UTC)