Talk:Elo Rating System for football

ELO RAnkings are wrong for Irish Team

All results of the Ireland team prior to partition of Ireland(The split of Northern and Southern Ireland)are included in the modern day Republic of Ireland team, whereas they should be included in the Northern Ireland team as they are natural succesor to the All-Ireland team.--Ifcp1 20:00, 25 September 2007 (UTC)

• Sounds like a reasonable argument, but Wikipedia is not the place to make it. You should raise this issue with the Elo ratings site maintainers. If it's changed there, Wikipedia will reflect the change, of course. Otherwise the most that Wikipedia could do would be to add a note about that concern, so long as it's reasonably sourced. Wantok (toktok) 01:09, 26 September 2007 (UTC)

That would depend, if the ELO ratings were derived from a governing body, you would be corret. However if the ELO ratings are derived from a formula, and the formula has been misapplied, then it is an issue on which WP can act without breaching WP:OR. Fasach Nua (talk) 14:15, 18 November 2007 (UTC)

In practice it just does not matter at all if you just regard today's ratings. Assuming that there really is a rating that correctly gives a team's strength (at a given time), then the rating will converge towards it and is self correcting for mistakes, so if both the Republic of Ireland and Northern Ireland played, let's say, 50 games after said event, their respective ELO ratings would not differ much anymore from the ones they would have if they had had a different starting rating. So todays ratings are as correct as if it were the other way round, only the ratings of the time immediately afterwards the split up would be messed.

"Just applying the correct data to the formula" is a bit of a stretch, though, since this data and the program calculating it are not as a compact block in the public domain, so first you need to collect all of the data, write a small programme working with it, and then pass the data through - just to find out (see last paragraph) that it hardly changes anything. --Ulkomaalainen (talk) 08:45, 7 January 2008 (UTC)

Yes i had contacted ELO to inform them of their inaccuracies, however they have not replyed. —Preceding unsigned comment added by Ifcp1 (talk • contribs) 01:17, 6 December 2008 (UTC)

Number of goals

In the current system the value of all goals exceeding the difference with more then three are the same. This doesn't seem fair to me. To my opinion a more fair formula for the goal difference index G would be (N is the goal difference; N > 0):

G = 2 - 21-N

Table of examples:

Goal Difference	Coefficient of K (G)	Proposal
+1	1	1
+2	1.5	1.5
+3	1.75	1.75
+4	1.875	1.875
+5	2	1.9375
+6	2.125	1.96875
+7	2.25	1.984375

In this formula the value of every extra goal decreases and the maximum multiplication value by extra goals is 2 instead of infinite as with the current formula. Otto 10:43, 6 May 2006 (UTC)

Your point is fair, the system is flawed, but I don't think Elo are concerned with preparing the formula for the eventuality of dealing with an infinite amount of goals ;-). Philc _T^E_C^I 00:51, 30 May 2006 (UTC)

If the goal difference is two, then you are multiplying by zero overall.

No, if you read the article, if the goal difference is two, you mulitply by ${\frac {3}{2}}$. Philc _T^E_C^I 10:18, 9 June 2006 (UTC)

I corrected the formula and added a table. The formula should now work for N>0. Otto 07:47, 10 June 2006 (UTC)

This article is hardly the proper forum to promote such a change. At any rate, it hardly seems fair that a team winning by a large margin would be limited to a double point gain. While such high scores are uncommon, they are certainly possible against lower-ranked teams.--BassoProfundo 17:26, 10 July 2006 (UTC)

Page Move

I think we should move the page to "World Football Elo Ratings" in accoradance with their website anyone opposed or have any points to make? Philc _T^E_C^I 12:38, 3 June 2006 (UTC)

Seems to me a good idea. Otto 15:45, 3 June 2006 (UTC)

how do you use the graph?

Pardon me if I'm a little slow, but how do you utilise the graph to extrapolate the expected result?

Ok well its annoyingly difficult ot describe but if the teams ratings are equal (i.e. diffrence = 0) then you read of from 0.5, and you get 0.5 so both teams get a W_e, and if the differences are 800 (the maximum) then you read off from 0.99, and the other team gets 0.10. all of the other results are spaced evenly between these two boundries (0.5 and 0.99) or below 0.5 for negative difference (i.e. the lower ranked team).

here are some examples.

Sample Winning Expectancies

Diff   Higher  Lower
0	0.500	0.500
10	0.514	0.486
20	0.529	0.471
30	0.543	0.457
40	0.557	0.443
50	0.571	0.429
60	0.585	0.415
70	0.599	0.401
80	0.613	0.387
90	0.627	0.373
100	0.640	0.360
110	0.653	0.347
120	0.666	0.334
130	0.679	0.321
140	0.691	0.309
150	0.703	0.297
160	0.715	0.285
170	0.727	0.273
180	0.738	0.262
190	0.749	0.251
200	0.760	0.240
210	0.770	0.230
220	0.780	0.220
230	0.790	0.210
240	0.799	0.201
250	0.808	0.192
260	0.817	0.183
270	0.826	0.174
280	0.834	0.166
290	0.841	0.159
300	0.849	0.151
325	0.867	0.133
350	0.882	0.118
375	0.896	0.104
400	0.909	0.091
425	0.920	0.080
450	0.930	0.070
475	0.939	0.061
500	0.947	0.053
525	0.954	0.046
550	0.960	0.040
575	0.965	0.035
600	0.969	0.031
625	0.973	0.027
650	0.977	0.023
675	0.980	0.020
700	0.983	0.017
725	0.985	0.015
750	0.987	0.013
775	0.989	0.011
800	0.990	0.010

--Philc _T^E_C^I 18:19, 7 June 2006 (UTC)

But the graph was $y=1-x$ not $y={\frac {1}{10^{-x/400}+1}}$. --Henrygb 21:46, 7 June 2006 (UTC)

Yes but if you look down the table the relation ship between the columns higher and lower is $y=1-x$. Philc _T^E_C^I 10:15, 9 June 2006 (UTC)

800 is not the maximum point difference. For example, compare Brazil with Palau on the ratings page.--BassoProfundo 17:31, 10 July 2006 (UTC)

Error in examples - loser should lose the same as the winner wins.

I might have missed something, but to me there seems to an error in the examples. The points lost by the losing team should always be the same as those gained by the winning team. At least, this is the case for all the matches I've seen at http://www.eloratings.net/. But, the tables in the examples seem to indicate different amounts for the winner and loser.

The error seems to arise because because a G value of 1 is assigned to the loser, when it should be the same as the G value of the winner, i.e. 1.5 for these examples. Rowandavies

Yeh your right, I just misenterpreted the system when I was wroking the tables out, feel free to change it, though I'll get round to it eventually if you don't but I've got alot infront of me right now. Philc _T^E_C^I 15:54, 14 June 2006 (UTC)

Done. Rowandavies 04:35, 15 June 2006 (UTC)

Thanks Philc _T^E_C^I 13:34, 15 June 2006 (UTC)

Conversation which has nothing to do with the examples shown

If the loser has to lose what the winner wins, shouldn't dr be (difference in ratings + 100) for the home team and (difference in ratings -100) for the away team? 82.155.55.83 13:54, 15 November 2006 (UTC) (User:Zé da Silva Not Logged In)

The examples are given as being played on neutral territory to simplify things, so home advantage is ignored when calculating dr. --Iae 15:30, 15 November 2006 (UTC)

That was not the point. I was talking about games in which one team plays at home. Zé da Silva 19:22, 15 November 2006 (UTC)

Well for some reason you wrote this under a section talking about errors in the examples so I assumed you were referring to the examples. To answer your question, yes, that is what should happen. Just artificially increase the home team's points by 100 and then do what you normally would. --Iae 19:56, 15 November 2006 (UTC)

Thank you for your information. Yes, I reckon it was not the smartest thing I could do writing under an examples section when I wasn't talking about examples. It was just the winner/loser part I was looking reassurance for. Zé da Silva 21:35, 15 November 2006 (UTC)

Which rankings should we use

http://www.eloratings.net/world.html http://www.eloratings.net/world_cup.html

Should we use the world rankings to update currently or the world cup rankings? W123 01:06, 16 June 2006 (UTC).

The first page linked to has the rankings pertaining to this article. BassoProfundo 17:10, 10 July 2006 (UTC)

Elo Ratings Calculator?

Hey,

Can I someone create an Elo Ratings Calculator that can be used to calculate domestic ratings? For example, it would accept a text document input of something like

ManU 3 Chel 1
Arse 1 Bolt 2

..and would output the overall table and the elo ratings? I know that a 3rd party magazine did this for american baseball, but I was wondering if someone was capable of programming something like this (preferably in C/C++) for other people to use...leave a message on my talk page, --Palffy 03:47, 11 July 2006 (UTC)

Why not do the calculations by hand? The formula is not that complicated. Once you get the hang of it, it should take less than a minute to calculate the new ratings after each match.

As the ratings work now, you would have to change the value of K to reflect domestic matches instead of internationals. You would also need a system for ranking teams as they are promoted and relegated.--BassoProfundo 14:27, 11 July 2006 (UTC)

Well, I could certainly work something out for the last two issues (such as taking Div 1 results into account only and only taking league matches into account--ie, no cup matches/friendlies), however, when you're plan on calculating 240+ matches/season (based on a H-A 16 team league), a program would certainly make this easier... --Palffy 21:06, 11 July 2006 (UTC)

There would still be some issues with that system; presumably you would want to keep the records continuously between seasons, but what about teams being promoted from the last season? And what happens to the ratings of teams that are relegated?

As for the program, I'm afraid that my knowledge of computer programming is far to limited to help you out.--BassoProfundo 02:54, 12 July 2006 (UTC)

Well, I think it would be a good first approximation to keep the ratings the same for the teams demoted from the premier league--ie, those teams would not be of interest in comparing teams (and would be kept separate from the competing teams). If the team would get promoted back to the division, it would simply retain the rating that it once had (which would be a low due to their previous poor season in the league---and would be near-equivalent to their strength level at that moment). What makes the ratings great, is that after 30 games or 1 season, the ratings would be properly calibrated for the club in question. As for clubs being promoted for the 1st time, they would start with an arbitrary ranking (comparable to those of clubs finishing near last in the league) similar to what the current elo rating has done (ie, countries start with an approximate rating and then achieve their real rating after 30 matches).

I could certainly try programming it myself, but my code is very inefficient and I would be unable to utilize the data effectively/efficiently that would allow me to calculate the ratings from 1000s of matches. --Palffy 03:36, 12 July 2006 (UTC)

I did something like this a while back. I parsed results from RSSSF premiership overview pages using regular expressions and incorporated them into an overall table using the ELO formulae. It still needs a bit of tweaking on the parsing and UI side of things, but it does the job. And yeah, I just assigned a provisional ratings to new clubs, like you suggest. Iae 14:26, 12 July 2006 (UTC)

You mind sharing this parser with everyone else? I tried to contact the guys who run EloRatings, and neither has responded to my requests..Quite unfortunate actually.. --Palffy 23:42, 13 July 2006 (UTC)

Yeah, of course. I've been meaning to just finish it off for a while anyway and i've got some free time for a while so i'll try and do that over the next day or two. Also, if you give me the format the files you want parsed are in (or, even better, e-mail me an example file, we shouldn't really be discussing this on the talk page anyway) then i can add some rules to allow it to be read. the more consistent the format then the easier it is to parse. Iae 17:52, 14 July 2006 (UTC)

What language are you programming the parser in? It would really be upto you as to how you want to make it initially...if its a language that I already know or I can pick up easily, I should be able to modify it accordingly (ie, I haven't really decided on how I'd want the input file to look like--that is, the file will probably require comments to separate seasons for easier browsing, but otherwise, anytype of format involving the names or a 3 letter code for teams should suffice followed by a score--after thinking about it, I think this would be the best format--its most similar to the data on RSSSF which I will use afterwards with the program..Post your email on your userpage if you'd like, and we can continue this over email..cheers!

ManU 3-1 Chel
Arse 1-2 Bolt

--Palffy 06:57, 15 July 2006 (UTC)

I've programmed it in .net because it's what i know best. I've never actually distributed a program before so i'm not entirely sure what you'd need for it to work, but at a guess you'd need the .net framework 2.0. Also, that format looks like it would work fine, and the parser gives you an option of converting any names (e.g. ManU to Manchester United) anyway so you wouldn't be forced to keep them in the 4 letter format. By the way, one small nuance is that each season has to go in it's own file and can only contain data for one competition. That shouldn't be too much trouble but just letting you know. Oh and you can e-mail me by clicking the 'Email this user' bit in the toolbox to the left of my userpage... i don't like putting it up available to everyone. Iae 12:22, 15 July 2006 (UTC)

I sent an email response as you requested =) --Palffy 20:10, 16 July 2006 (UTC)

At least for single play Elo coefficient calculations, the Freeware program "WorldCupRatings" should be useful: www.worldcupratings.sourceforge.net --xblop 02/08/2011

FIFA verses ELO

I think it would be a good idea to put a side by side comparison of the top teams in Elo rating next to the top teams in the current FIFA system. Somthing like this

Top 20 FIFA Rankings compared to Elo
FIFA Rank	Team	Elo Rank
1	Brazil	3
2	Italy	1
3	Argentina	4
4	France	2
5	England	5
6	Netherlands	6
7	Spain	7
8	Portugal	9
9	Germany	8
10	Czech Republic	11
11	Nigeria	22
12	Cameroon	21
13	Switzerland	12
14	Uruguay	14
15	Ukraine	24
16	Mexico	16
17	Denmark	10
18	Ivory Coast	25
19	Paraguay	28
20	Sweden	13

24.237.198.91 05:58, 24 August 2006 (UTC)

I wouldn't be against this, it could even be implemented into the main table. However, I think there should be a specific section detailing the advantages ELO rating claims to have over FIFA (as opposed to having them dotted all round the article) and vice versa, as well as mentioning about the switch in FIFA system and how it changes things. Other views? Iae 10:13, 24 August 2006 (UTC)

Good idea. I've just added a 'FIFA rank' column. A section explaining differences would also be good, and some examples comparing the two. The examples used on the FIFA ranking page could be a starting point - or perhaps there are too many to be clear (I wrote the explanatory sections on the current FIFA system). -- Wantok 11:30, 24 August 2006 (UTC)

I think the main arguments for FIFA is tht they show how well the teams have played over the past couple of years, thus rewarding consistancy. and that the main argument for Elo is that it shows how well they are playing right now. and doesn't punish teams for a bad season 8 years ago. 24.237.198.91 22:16, 24 August 2006 (UTC)

Well I'd say the opposite really. ELO takes into account ALL results for a team no matter how long ago they were, a result of the rankings' chess roots where that data would be relevent. FIFA assigns as arbitrary cut-off (I believe it's 4 years in the latest version) which in a football context does make more sense. Iae 22:37, 24 August 2006 (UTC)

I'm going to have to disagree because if someone has a bad beggining in chess (Or football) as they get better the elo system will give them points to make up that difference. 24.237.198.91 03:57, 25 August 2006 (UTC)

Well, the models are fundamentally different in structure, in that the FIFA score is recalculated each month based on the previous 4 years' results (with the last year counting for more than the year before, etc). Thus a team's score can change significantly from one month to the next, without the team playing a game, because a match played a year ago, or 2 or 3 or 4 years ago, has dropped in value. And in the FIFA system, a team never gets negative points from a game - the only reductions are from older games losing value. Elo points only change as a result of games played now, and a team loses points if they do worse than expected. So the Elo points are a kind of running total that's incrementally increased or decreased based on games played now, whereas FIFA's total can only be increased by games played now, and can only be decreased by the passage of time. The latter seems disjointed and asynchronous. To me, Elo seems a more sensible approach.

Another problem I have with the FIFA system is the whole confederations-weighting thing. Arbitrary and discriminatory. There's already a weighting based on the opposition's rank in the world; why add an additional factor to increase the points of the strong confederations and reduce the points of teams in the weaker confederations? Very dodgy, in my book. Elo has no such nonsense. -- Wantok 06:11, 25 August 2006 (UTC)

Yes, I have the same view when it comes to the arbitrary confederation rankings, done seemingly just to keep the traditionally big national federations happy. I don't think the two models are as fundamentally different as you make out though. It's true that the only way to "lose" points is when an old result disappears behind the 4-year cut-off point but this is the same in all fixed-length ranking systems, there's no other way about it. If we're going to be comparing the two systems then we can't just go writing a list of good things about ELO. The fact FIFA doesn't include results from 1960 which have no bearing on the quality of a team today is an obvious advantage.

Oh, and "FIFA's total can only be increased by games played now, and can only be decreased by the passage of time." makes sense to me. Team's change considerably in the passage of time, it's a perfectly good variable to use. Iae 11:34, 25 August 2006 (UTC)

Elo rankings more inclusive than FIFA rankings

Shouldn't there be a mention of ELO rankings including non-FIFA teams? Highest ranked non-FIFA team is Turkish Republic of Northern Cyprus, which is a member of NF-Board.

1970s

Why are bot the Strongest football nations by Elo Ratings and the Top 10 in this article caltulated since 1970?? There seams to be no reason to ignore previous years. I'm not sure how far back the available relevant information goes, but I would think it goes way back since there's a Top 20 per decade since 1950. There are coutries that are very much relegated because of this ommisions, most notably Uruguay.

Here are the 1872-2008 statistics.

--Mariano(t/c) 13:17, 12 April 2007 (UTC)

This discussion moved to Talk:Strongest football nations by Elo Ratings -Afasmit 01:36, 13 April 2007 (UTC)

Clutter

Someone copied the "strongest teams by decade" tables from the Strongest Football Nations by Elo Ratings page to this page. Though I (of course) agree that that is very interesting information, this page is becoming very cluttered and you have to scroll a long way to the bottom to get the Elo rating actually explained. I believe this page really should focus on the method and the current results, with links to pages showing stats. Anyone object if I remove the decade tables again? Perhaps we can prune elsewhere as well. Afasmit (talk) 04:58, 6 September 2009 (UTC)

Website

I can't connect to the ELO website. Has anyone else managed to do this recently? Exile (talk) 20:23, 28 September 2009 (UTC)

This has been a recurrent thing. I don't know what the issues are, but so far the website kept coming back. Wouldn't be good for this article and its spinoffs if the site permanently disappears. Can someone provide these people with a stable website, please ;-) Afasmit (talk) 00:53, 29 September 2009 (UTC)

Portugal

There is any reference of Portugal team in 1966, according to numbers, on the nª3 of the ranking in that year. —Preceding unsigned comment added by 85.138.43.229 (talk) 21:48, 20 April 2010 (UTC)

Complete World Cup Simulation as Freeware

Based on the Elo ratings, it is also possible to calculate probabilities for a complete tournament if all future scenarios are considered. I've written the program "World Cup Ratings 2010" based on OpenOffice.org that performs the mentioned calculations for the World Cup 2010 and published it as freeware. It can be downloaded here, for example: http://www.file-upload.net/download-2455021/WorldCupRatings2010v1.0.zip.html All scenarios possible in the future (they're a lot) are taken into account. After each play, updates are possible. I've compared the results with predictions of several banks and with odd quotas and found big similarities. —Preceding unsigned comment added by 84.150.82.181 (talk) 18:23, 24 May 2010 (UTC)

Is it appropriate to advertise software through a talk page like this? BassoProfundo (talk) 20:14, 24 June 2010 (UTC)

Updating for 2010 World Cup matches

There are some problems waiting for the elo website to release new ratings after WC matches. While the formula does allow us to calculate results, it does not mean we should. Our object should ONLY be to update the ratings as the website does, otherwise it is original research per WP:OR. Note that this is only a problem because the speculative updates are usually wrong. Barronitaly (talk) 13:59, 14 June 2010 (UTC)

I'm pretty sure that, because the elo score calculations are defined and deterministic, WP:OR doesn't apply. The updates are akin to adding a win to a winning streak of a sports team, a new time to the an alltime record list, or a new sale to the most expensive paintings list. We don't have to wait until an official list (which often doesn't exist) has included the data. I believe our case is covered by WP:OR#Routine calculations. Despite our goofs, we pretty much "add numbers" as mentioned in that paragraph.

We do occasionally goof up (like I did yesterday weighing WC matches as 50 i.s.o. 60), but other editors catch the errors really quickly, and "Kirill", the maintainer of the website now and then fixes errors as well, which ripple throughout the database. Worse, the website can lie dormant for up to 4 weeks in a row and sometimes it isn't accessible for days. The updates at the website are currently and understandably actually far quicker than usual.

Be aware that if you push WP:OR too far, as many people are inclined to do, very few edits on wikipedia will eventually pass muster. Afasmit (talk) 23:45, 20 June 2010 (UTC)

In retrospect I think you're probably right. So far we've been pretty good about updates. However, there were some edits leading up to the WC (and including the first few matches, it seems) that were way off, calculating half the correct values or not adding and subtracting the same numbers. +16 and -12 one time as I recall. I was just trying to find a policy that would keep novice editors from jumping the gun poorly. Barronitaly (talk) 02:35, 21 June 2010 (UTC)

There is no external source with the new Elo ratings. Updating them without a source is WP:OR. The current external source is Football rankings website. Regards. --Drime (talk) 03:54, 8 July 2010 (UTC)

I support Afasmit's notion that this goes under WP:OR#Routine calculations. The formula is public and it's possible to review calculations.Lejman (talk) 20:31, 10 July 2010 (UTC)

I really think we pushed the WP:OR#Routine calculations too far. Yes, the formula is public, but we didn't have info on Tunisia's or China's friendlies which affected the top 60's list. That's why I didn't think it was a good idea to update this on our own. Knowing the formula isn't all. We needed all variables, and we don't have them. --Drime (talk) 09:34, 20 July 2010 (UTC)

Color for OFC

New Zealand's tie with Italy in June 2010 put an OFC nation on the chart. Since there wasn't an OFC nation already I picked a pastel-ish color that wasn't being used already as a temporary color. I don't know if there is a color for OFC already...is there a chart somewhere? —Preceding unsigned comment added by Barronitaly (talk • contribs) 02:21, 21 June 2010 (UTC)

• Confederation colours are here. Wantok (toktok) 07:22, 25 June 2010 (UTC)

Elo site

By the way, it's been down for several days, making it difficult to verify the ratings. Enigma^msg 18:13, 28 June 2010 (UTC)

Well there's this but I don't know how official it is. http://www.football-rankings.info/2010/06/elo-ratings-update.html Obviously freakin Turkey or Croatia aren't leading the table as recent vandalism has shown. Pik d (talk) —Preceding undated comment added 18:42, 28 June 2010 (UTC).