Talk:Two-party-preferred vote

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The more common way to describe it is 40-30-30, with candidates B and C sharing similar values, with candidate B overtaking and beating candidate A, with candidate C's preferences. Timeshift (talk) 10:01, 18 July 2010 (UTC)

Note that the article says: may be necessary to continue distributing preferences beyond the point at which the winner of the vote is known. For example ... Candidate A has more than 50% of the votes, so will be declared the winner ... However to determine the two party preferred result, ..."
Ie the example is not intended to show how instant run-off voting can given the win to someone who did not get the highest primary votes (that's for the IRV article to do), but how calculating 2PP may require distribution of votes even after the winner is known. Mitch Ames (talk) 10:12, 18 July 2010 (UTC)
Although I probably should pick numbers that give a different margin between A and B for primary and 2PP values, for it to be a good example. Will fix that soon ... Mitch Ames (talk) 10:16, 18 July 2010 (UTC)
Done. Mitch Ames (talk) 12:46, 18 July 2010 (UTC)

Three candidates only demonstrates instant run off voting. You need at least four candidates to demonstrate 2CP --Surturz (talk) 12:58, 1 September 2010 (UTC)

I don't understand why - could you explain please? Mitch Ames (talk) 14:29, 2 September 2010 (UTC)

Commonwealth Electoral Act 1918 as amended, page 300 is the part that discusses when and how TCP is used. --Surturz (talk) 01:03, 2 September 2010 (UTC)

I couldn't find a reference to either 2PP or 2CP. Exactly which section/paragraph/clause are you referring to? Mitch Ames (talk) 14:29, 2 September 2010 (UTC)
Part XVIII, Section 274, Subsection (7AA) paragraph (b) (ii) (yes, really :-). I think it is on page 301. Note, I am using the actual page number on the bottom of the page, not the page number in the PDF. PDF page number is 319. Subsection 7(d) describes run-off voting, Subsection (7AA) describes TCP. --Surturz (talk) 00:09, 3 September 2010 (UTC)
(7AA)(b)(ii) does indeed describe the AEC's TCP, however:
  • The AEC's definitions of 2PP/TPP and 2CP/TCP are not the same as those in the Wikipedia article - see #Contradiction: Two-candidate-preferred (TCP) vote below.
  • (7AA)(b)(ii) does not require 4 candidates for 2PP or 2CP (of either AEC's or Wikipedia's definition). Whether there are 3 or 4 candidates, you need to distribute their preferences to get the 2PP/2CP count. Nothing in (7AA)(b)(ii) or (7AA)(c) require more than three candidates in total.
I still think my example with three candidates is sufficient for illustrating 2PP as defined in the lead para of the Wikipedia article, but feel free to update it to four candidates if you think it necessary. Mitch Ames (talk) 12:10, 3 September 2010 (UTC)
TCP counting is all about reducing the number of counts required to determine the victor (to two counts). By corollary, TCP is about ignoring preference allocations that don't affect the result. A three candidate election TCP has the same number of counts as a three candidate IRV count; it does not exhibit the difference. I'm developing a better example, but it is hard getting the level of detail right. You really need to show a ballot paper and the process of ignoring intermediate preferences. --Surturz (talk) 15:01, 3 September 2010 (UTC)
OK, I think I get your point now. With 3 candidates only, a strict instant-runoff count - as per Electoral Act paragraph (7AA)(b)(i) and (7)(d) - and a TCP count - as defined by AEC VTR and (7AA)(b)(ii) - require the same number of counts (of preferences etc). However with 4 or more candidates the AEC's TCP count requires fewer counts than strict instant runoff, because the AEC's TCP does not require distribution (ie counting) of votes from 4th (and lower) ranked candidates to 3rd (via 4th etc) before distribution to the 2 leading candidates. Note that this assumes that the AEC correctly predicts the two leading candidates. The AEC VTR definition says they will "predict" them, eg on historical data, but the Act (7)(ca)(i) says that they must actually count them. Your example may need to take this into consideration.
That being said, my example with 3 candidates is not intended to demonstract the AEC's TCP count, but rather than two-party-preferred vote as defined in the lead section of the article - in which case 3 is sufficient. There may be merit in an example with 4 candidates to illustrate the AEC's TCP method, and how it reduces the count - but I think we must first clarify the definitions of TPP and TCP. As per #Contradiction: Two-candidate-preferred (TCP) vote below, the article is not clear or consistent about what the terms are, and replacing my example with one that illustrates the AEC TCP method will only muddy the waters. Mitch Ames (talk) 08:53, 4 September 2010 (UTC)

Name change is essential[edit]

First, please note that a hyphen is a must: Two-party preferred. The other MoS issue is that the name needs to be a nominal group, i.e., a noun (phrase). Two-party preferred what? I suppose it can't be "vote", can it? That would be the most intuitive for readers. Tony (talk) 02:07, 22 July 2010 (UTC)

Two-party-preferred? Another Tonyism it seems... Timeshift (talk) 00:42, 23 July 2010 (UTC)
You link us to a google search that shows the correct hyphenated form in the first two entries. I don't get it. Do you think I control those sites? Tony (talk) 00:45, 23 July 2010 (UTC)
It seems your interpretive skills are somewhat lacking. I searched for the term with two hyphens, the only site to come back using two-party-preferred is not exactly a WP:RS. I'd feel much more comfortable using two-party preferred found in... you know... WP:RS? Just a thought............ Timeshift (talk) 00:48, 23 July 2010 (UTC)
I see there's another breach of WP:CIVIL (have you read it?). Making bald criticisms about other editors "skills" is a definite no-no. It is quite different to make bald criticisms of article text. I believe google searches are not sensitive to hyphens. In any case, you might consider reading WP:MOS#HYPHEN. Tony (talk) 01:35, 23 July 2010 (UTC)
Your interpretive skills in reviewing the google results for who uses the term "two-party-preferred" are somewhat lacking. Only one site, and not a reliable one, uses it. Timeshift (talk) 01:44, 23 July 2010 (UTC)
  • Again, this is a breach of WP:CIVIL. Do not criticise other editors' skills. Just state what you believe to be the issue without personalising it. I am adding this to the list of diffs I will take to AN/I if necessary. Tony (talk) 02:00, 23 July 2010 (UTC)
So, what we have at the moment is the double-hyphenated "Two-party-preferred" in the title, but the very first mention of the term in the article, bolded in the lede para, has only 1 hyphen. What gives? -- Jack of Oz ... speak! ... 20:03, 26 August 2010 (UTC)


There's no mention of any particular country, but we have "When it is not referring to a Labor and a coalition candidate, it is better known as the two-candidate preferred vote". That is obviously about the Australian context. -- Jack of Oz ... speak! ... 20:03, 26 August 2010 (UTC)

I've removed the reference to specific parties. Mitch Ames (talk) 11:01, 27 August 2010 (UTC)
is there any evidence that TPP is not peculiar to the Australian electoral system? I think this article should go into more depth about the way it is used in Oz. --Surturz (talk) 12:00, 1 September 2010 (UTC)

To offer a perspective from outside Australia: on reading the first paragraph, I felt it needed to mention Australia somewhere. I decided not to start off with "In Australian politics ...", because I am allowing for the possibility that the concepts might exist outside of Australia, even though the article specifically references the Australian defintions. I therefore simply edited to show that the example comes from the 2010 Australian federal election. I just wanted to make it clear in the article text which country's election we are talking about, and not require the reader to inspect the Wikilink to find out. Wdchk (talk) 00:15, 25 February 2011 (UTC)

Contradiction: Two-candidate-preferred (TCP) vote[edit]

The lead sentence defines TCP as the term used to describe a TPP when one or both candidates is not from a major party. However the Two-candidate-preferred (TCP) vote section describes a specific "short-cut" (by presuming the top two candidates) to determine the winner, regarless of whether those top two candidates are members of the two major parties.

Ie the first definition says TCP is a synonym for TPP, used when one or both Candidates are not one of the major Parties. The second definition is a different means of determining the winner.

Some clarification is needed. Note that AEC Virtual Tally Room notes (the origin of our article's second TCP definition) define TPP differently to our article. I'm not suggesting that we should use their definition, but their definition of TPP may help understand the context of their use of TCP. Mitch Ames (talk) 11:45, 3 September 2010 (UTC)

The AEC have specific, different, meanings for TCP and TPP. I think it is common to use the term TPP to mean both. I doubt many people know the difference, because it is a subtle distinction. --Surturz (talk) 14:54, 3 September 2010 (UTC)
Note that the AEC VTR definition of TCP says that they will select/predict the likely two leading candidates, but the Electoral Act paragraph (7)(ca)(i) says that they must actually count them. Ie the TCP candiates may change after the primary count. Mitch Ames (talk) 09:06, 4 September 2010 (UTC)
This can and does occur, and is mentioned in the article. --Surturz (talk) 02:30, 7 September 2010 (UTC)
FWIW, and I acknowledge there are quite reasonable alternative points of view, I think I would prefer at this stage reworking the article to be a very good description of TPP and TCP as the terms are used by the AEC. Once that is done, we can broaden the article to talk about the TPP concept more broadly (ie. how opinion polls use it, which is a bit different), and also to give some historical background (e.g. why TPP was invented by the AEC in the first place). Instant-runoff_voting#Two_round_systems is clearly a related concept, so I would suggest that TPP is the Australia-specific version of that. There are currently very few refs in the article, so I think a bit of ref hunting is in order too. --Surturz (talk) 05:40, 13 September 2010 (UTC)

Tags just can't be left indefinately on articles. If it's a concern, please fix it, but I see no real issue with the article, especially not tag-warranted. Timeshift (talk) 21:05, 14 November 2010 (UTC)

I've restored the {{Contradict}} tag, because the article is still not consistent. If anything it's worse now. I would fix it, but I don't know what the correct definitions are, or should be - I'm not an expert on politics. But the article clearly needs some work. In summary, the article now has three different meanings for 2CP:
  • A synonym for 2PP, if the 2 preferred candidates are from the major parties
  • A result different to 2PP if the 2 preferred candidates are not both from major parties. (Ie the same seat and election has both a 2PP and a 2CP, with different values.)
  • A short-cut method of determining the winner (as described in the "Two-candidate-preferred (TCP) vote" section).
The latest additions cited this reference of "eight ... seats returned differing 2PP and 2CP figures" but that reference:
  • does not show the "differing 2PP and 2CP figures"
  • does not mention 2PP or 2CP (it says "non classic Candidate Preferences")
  • does not mention more than one major party for each seat (ie "indicating a considerable two-party system").
Thus I do not think that reference justifies the new definition of "differing 2PP and 2CP figures".
It may well be that 2PP and 2CP mean different things in different contexts, but the article needs to say so explicitly, and describe the different meanings and their contexts clearly. It also needs to cite appropriate references - as I mentioned don't believe that "Non-classic divisions" is suitable. Mitch Ames (talk) 12:10, 15 November 2010 (UTC)
My view is that we should use the AEC definitions, viz.
  • Two candidate preferred (TCP) - refers to a distribution of preferences of the two candidates who are expected to come first and second in the election. Often, but not always, these will be the candidates representing the ALP and the Coalition (Liberal, National or Country Liberal Parties).
  • Two party preferred (TPP) - refers to a distribution of preferences where, by convention, comparisons are made between the ALP and the leading Coalition candidates. In seats where the final two candidates are not from the ALP and the Coalition, a notional distribution of preferences is conducted to find the result of preference flows to the ALP and the Coalition candidates.[1]
The use of "Two party preferred" in the context of opinion polls could then be described in a subsection, provided refs were supplied. All the refs I have seen describe TCP/TPP in the Australian context, I am not convinced the terms are used in other countries. --Surturz (talk) 02:38, 16 November 2010 (UTC)
Surtz, the AEC defines 2CP in the context you found it in. Review this as an example, read the bottom, and then come back and tell us what 2PP and 2CP is. I'll tell you. 2PP is Labor v Coalition. 2CP is the highest two candidates after redistrib of prefs. 2CP is the 2PP if the final result is Labor v Coalition. Thanks. Timeshift (talk) 06:08, 16 November 2010 (UTC)
I think we agree here. It should be noted that individual seat 2PP counts aren't very interesting, it is the national 2PP count that is important. The AEC website generally concerns itself with National TPP and seat-by-seat TCP.
I think it is worth reviewing WHY this article is useful at all. The National 2PP is important in linking opinion polls to election results. By working out the 2PP swing, commentators can estimate the number of seats that will change hands (cf. Mackerras Pendulum). Opinion polls have small sample sizes that measure national sentiment, not seat-by-seat swings. Without 2PP, Opinion polls would be hard to relate to electoral outcomes. The article confuses itself by tripping over itself to describe the HOW, without discussing the WHY. --Surturz (talk) 06:49, 16 November 2010 (UTC)
That was a rather wild tangent - I don't agree. Please go back to the definition of 2PP (two party preferred) and 2CP (two candidate preferred). You were applying the 2CP AEC definition out of context. We have 2PP and 2CP at a seat level. Every seat's votes are redistributed to get the 2CP, example here. The result is the same as the 2PP result. 142 of 150 seats had the same 2CP and 2PP. In the 8 seats that were not Labor v Coalition, example here, the 2CP was not Labor v Coalition, so for informative purposes there continues to be a 2PP which works by distributing to the major parties to get a seat 2PP (good to see 2PP swings), and also to properly calculate the informative national 2PP. This is where/how they apply and what they are. I am however in agreeance that the article or at least the description could do with an overhaul. Does it really warrant a "contradiction" tag though? Timeshift (talk) 06:55, 16 November 2010 (UTC)
I'm inclined to agree with TS9 on this. Tony (talk) 08:32, 16 November 2010 (UTC)

To hyphenate or not to hyphenate[edit]

The item "two-party-preferred vote", currently the title of the WP article on this topic, has been the subject of debate about whether it should be hyphenated. I sought advice from User:Noetica on this. His response is on my talk page, collapsed. I'd be pleased to receive feedback. Link Tony (talk) 06:37, 8 September 2010 (UTC)

  • NO HYPHENS - – — Great, now you are wasting other editor's time as well. You can quote as many newspapers as you want, you can quote as many style guides as you want, but you cannot change the fact that the AEC defines these terms, and they do not use hyphens. Newspoll also generates TPP data, and they do not use hyphens.[2] Galaxy research generates TPP and they don't use hyphens.[3].
The case is clearly mounting against you. It isn't easy getting these opinion polls to talk, you know. It took a lot of aromatherapy, a non-threatening environment and gentle leading questions like "Can you show me on the opinion poll doll where User:Tony1 hyphenated you?"
And since when were Google hit–counts WP:RS anyway? That's a no—no. --Surturz (talk) 07:38, 8 September 2010 (UTC)
On the website of the Australian Electoral Commission, this page uses the hyphenated forms "two-party-preferred results" and "two-party-preferred figure". This page uses the hyphenated form "two-party-preferred vote count". This page uses the hyphenated form "two-party-preferred". This page uses the hyphenated form "two-party-preferred".
Wavelength (talk) 02:48, 10 September 2010 (UTC)
Even the AEC is not always consistent: their virtual tally room [4] [5] [6] does not hyphenate. Perhaps more importantly their glossary does not hyphenate. Mitch Ames (talk) 03:39, 11 September 2010 (UTC)
Is the AEC only reference we have for TPP and TCP? Are both of these purely Australian terms? Perhaps we should resolve #Contradiction: Two-candidate-preferred (TCP) vote first? Ie clearly define the terms and their origins before we argue about whether hyphens are required. Mitch Ames (talk) 03:31, 11 September 2010 (UTC)
No, but it's all over the SMH and The Australian, and other news sources. And as Noetica points out, the main style guides in the US, the UK and Australia (including the AGPS) insist on the hyphenation of such compound units. Tony (talk) 06:05, 11 September 2010 (UTC)
Just for the record, I don't (currently) have an opinion on the matter of hyphenation. However I do believe that citing sources is meaningless if the sources are using the terms to mean something different to our article - hence #Contradiction: Two-candidate-preferred (TCP) vote. Mitch Ames (talk) 06:31, 11 September 2010 (UTC)
Agree with Mitch. Settling the issues of substance are more important than quibbling over hyphens. I won't be edit—warring over hyphens, it just is not that important. Keep your stupid hyphens. --Surturz (talk) 05:34, 13 September 2010 (UTC)
That seems a bit defeatist. If the AEC glossary does not use two-party-preferred then neither should we. Two-party preferred is the common format. Timeshift (talk) 05:42, 13 September 2010 (UTC)
  • So you declare, but I see "two-party-preferred X" all over the place. Here's another I just happened upon. Apart from the fact that it's illogical not to group the compound adjective as three components. Tony (talk) 08:13, 13 September 2010 (UTC)
Funny you should paste that link, google "two-party-preferred" and that site is the only result you'll get that hypenates party and preferred :) Timeshift (talk) 14:51, 13 September 2010 (UTC)
There are tons. Tony (talk) 16:59, 13 September 2010 (UTC)
After reviewing Google news hits for "two party preferred vote", it would appear as though "two-party preferred" is slightly more common than "two-party-preferred" and that "two party preferred" is rarely used; therefore, per WP:COMMONNAME I'd lean towards "Two-party preferred vote" as the correct title for this article. NickCT (talk) 17:32, 17 September 2010 (UTC)

Inconsistent issue[edit]

I can't keep up with the tag, on again off again. What is inconsistent, please? Tony (talk) 12:06, 15 November 2010 (UTC)

Details are in #Contradiction: Two-candidate-preferred (TCP) vote above. Mitch Ames (talk) 12:16, 15 November 2010 (UTC)

Does the article seem clearer now? Timeshift (talk) 22:52, 29 February 2012 (UTC)

See my new #Comments on the re-write, 2012-03 below. Mitch Ames (talk) 03:13, 3 March 2012 (UTC)

Example suggestion - lose the swing and informal votes[edit]

The recently added examples (Federal, Adelaide 2004, Frome, South Australia 2009) include percentage change from previous election and informal vote count. I suggest that we remove those items because they are not part of the example calculations, and they may just distract readers from the data that matters. We probably need to note that the percentages in the 1st count don't add to 100% because of informal votes, however percentages in subsequent counts are of the formal votes only. Mitch Ames (talk) 09:08, 19 February 2012 (UTC)

Comments on the re-write, 2012-03[edit]

I see there's been quite a lot of work on this article lately, but there still seems to be a few problems with it. I'm not an expert in politics, so I can't just fix most of it - some of my understanding of the topic may be incorrect.

  • The lead section does not - but probably should - mention that the 2PP/2CP is the percentage (usually) of votes for each of the two preferred parties/candidates after distribution of preferences. Defining it as "express a ... vote after the distribution of preferences" is not sufficient because it doesn't explicitly indicate that the 2PP/2CP result tells us not just how much the winner won by, but also who the major opponent was.
  • Corollary to the above: the lead should briefly mention why the 2PP is important.
  • The lead paragraph as currently worded implies that 2PP and 2CP are synonyms - ie it says "the 2PP, or 2CP, ..." and doesn't mention that they are not always the same. Yet the cited reference (AEC glossary) defines them differently. (We mention the differences later, but the lead paragraph should standalone as an accurate summary and not mislead the reader.)
  • The article is explicitly about Australian politics, we rely heavily on the Australian Electoral Commission for references, and the lead paragraph cites the AEC glossary for definitions of the terms. Given that we are using AEC definitions, I suggest that we should use the same abbreviations as the AEC glossary, ie TCP/TPP, not 2CP/2PP.
  • The AEC glossary explicitly defines the TCP as "where preferences have been distributed to the likely final two candidates" - where I presume "likely" is still based on "available information such as historic voting patterns". Based on this definition, we should probably note that TCP may vary in some cases during an election count. The nature of the TCP as defined by the AEC Glossary is that it is used as an early indicator of results during counting - not just a static result at the end of the count.
  • The article (after the lead section) distinguishes between 2PP and 2CP, stating that they are not always the same and even giving examples, but doesn't give any indication of how the 2PP vote is determined when it not the same as the 2CP. (This AEC page just says "a notional distribution of preferences to find the result of preference flows to the ALP and Coalition candidates".)
  • The article notes that "opinion polls [always produce a a 2PP] ... calculated based on preference flows at the preceding election rather than at the time of polling". It's probably worth noting why they do this.
  • We could probably remove some of the "commentary" in the examples - eg "the result being uncertain for over a week", "By 21 January 2009 ...", "The commissioner rejected a request for a recount...", etc. It doesn't add any value to the illustration of the 2PP/2CP methodology, or why the final 2PP/2CP values are important (eg for swings).
  • I suspect that History section is too long, and could be trimmed. Eg the first paragraph seems to be more the history of full-preference instant-runoff voting, rather than 2PP. Possibly the penultimate paragraph could be moved into a separate section about where 2PP is and is not used.

I'll probably fix the more trivial of these (eg TPP vs 2PP), unless someone explicitly objects. Other points need may need some discussion (or pointing out my mistakes!) or addressing by someone who better understands the issue. Mitch Ames (talk) 03:12, 3 March 2012 (UTC)

I pretty much agree with all your points, except for the last one. I think it is crucial as to the background of how 2PP came in to existance. That said, i'm not against the repositioning of paragraphs in new or existing sections. You mention how they calculate the TPP when the TCP is different, well i'm not sure how to put it in to encyclopedic wording but they just distribute the non major party candidate's preferences rather than the third placed major party candidate preferences to get the TPP. I can't readily recall a situation where a major party has finished fourth, i'm not sure what would happen in that situation, probably the non major party lowest vote candidate gets their preferences redistributed and then the other non major party candidate. I've fixed the 2/T issue, trimmed Frome commentary, made some lead changes, and some other bits. What do you think of the current state of the article? (updated comment) Timeshift (talk) 12:28, 4 March 2012 (UTC)
I thought the lead section was still a bit vague, to I rewrote it completely. Now I think it better meets WP:LEAD, in particular: explaining exactly what TPP and TCP actually are, how/why TPP, TCP differ, and why the TPP is important.
Possibly some other sections still need work.
  • I'd like to see the Procedure section tell us exactly how the TPP is calculated when the two remaining candidates (after preference distribution) are not from the major parties.
  • I can't believe we need five lengthy examples, with running commentary, to illustrate the concepts.
  • The list of federal results is probably overkill - is there a separate article we could link to instead?
Mitch Ames (talk) 07:14, 11 March 2012 (UTC)
I dont mind shuffling bits around but I think everything here is relevant and important. Timeshift (talk) 07:39, 11 March 2012 (UTC)

Further thoughts, split: Federally & general:

  1. I'm a bit confused about how contests with both Liberal and National candidates are handled - the current wording implies that a National is only used when no Liberal is in the field but most such 2CPs with the Nationals & Labor don't appear to have separate 2PPs.
  2. Also regarding which Nats are and aren't included, my recollection of the last election is that the Nationals candidates in Western Australia were regarded & counted by the AEC (& ABC) as Nationals like any other, being nominated by the registered federal party, regardless of state branch autonomy or the caucus intentions of the candidates. (The WA Nats did raise objections but seemed to want votes allocated one way and Crook another which was refused.)
  3. How does the AEC handle situations when the Coalition splits - are the 2PPs for 1987 just based on the Liberals or a notional coalition representing that side of politics?
  4. Similarly for 1987 how did it handle the Nationals' own split and the rang of Joh candidates?
  5. How does 2PP handle a situation where a party fields more than one candidate? The Country Liberals have a particular record of doing this and would have done so in Lingiari in 2010 if the law hadn't been changed by the CDP's antics.


  1. Again there's the whole mess of how to handle the Nationals, especially in states where Coalition relations have been on & off quite frequently, and I get the impression that the state commissions have taken different approaches both in different states & at different times.
  2. I think the article could use a specific table of just what 2PP was used at the most recent elections in each state. ISTR talk that 2PP was abandoned in Queensland with the rise of One Nation, but the results for Saturday suggest it may be back. WA seems to have shifted to a Liberal (& endorsed independent in a seat without a Liberal candidate)-only 2PP. I think SA has always been Liberal-only and also the 2PP there has never included the various minor parties & independents even when they end up in government (and in the relevant election article 2PPs - these could use a sort through to clear up this hybrid data).

Timrollpickering (talk) 12:51, 27 March 2012 (UTC)

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