Football: Indian National Team news ...

General Discussion on Indian Football.

Moderator: Moderators

User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

Oh WOW!!

what a nice little mystery (868) to be solved
jayakris wrote: Tue Aug 21, 2018 3:01 am I had to rack my brains for a while to figure out what they did to get that number, 868. I think I just figured out what it was. The little hint was an unimportant-sounding note at the FIFA page that said, "The previous ranking table was converted into a new table without displacement in the order of the teams; i.e. each team retained its relative rank position. In instances where teams shared the identical rank (R), the teams which followed were given the next immediate rank possible. Example : If there were two teams in position no. 11, they both got R = 11, and the following team got R = 12 (instead of R =13)"... Sounded like mumbo-jumbo, but...
... :notworthy: :clap:
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

jayakris wrote: Tue Aug 21, 2018 3:01 am But do we agree with points being in somewhat of a linear scale from the top to bottom, in the starting seed points list. I am not an expert on ELO to say if that is normal in ELO football rankings. Did the earlier independent ELO rank lists show a somewhat linear trend from the top rank to the bottom rank? Is it fair to do this? Yes, it worked for FIFA to save their behinds and produce a rank list that preserved the earlier ranks and caused reasonable changes at the top after world cup. But what about going forward? Won't this screw things up in ELO? Experts, please chime in...
As for the ELO impacts, few thoughts:
1. This seems to imply that the TOTAL ranking points is going to be constant from now on. Team A wins and gains say 15 points, while Team B would lose the same 15 points. So the net ELO points remains the same....

But in reality - Chess has been using ELO for a long time now - we need to have some infusion of points into this stagnant pool of ELO points... This happens naturally, when new players start getting ELO points in Chess. But in Soccer, we rarely have new teams / countries coming in...

2. When I read the second page on PSO (penalty shoot out) and the Knock out rounds part of the FIFA document - it really is an infusion of FWR ELO points into this pool!! So, that is good - although the worry is,
a) typically we have quite a few Drawn matches in Soccer, during the course of a tournament which results in a penalty shoot out.
b) more than PSO, the notion that knockout rounds will infuse points to winner of the match (17 or 25 in worldcup), while the losing team gets to keep its points the same as before... This will infuse a lot of ELO points resulting in inflation.

3. Inflation of points is good, but has to be controlled. Not sure how to account for 2 b, but I suspect in a couple of years time we will have a good idea on how much new ELO points are being added to the pool on a yearly basis....
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

We_progress.jpg
We_progress.jpg (21.74 KiB) Viewed 3297 times
so, I plotted the progression of We in relation to the current ranking of two teams (x axis). For example, If the top ranked team and the 100th ranked team were to meet in a Friendly during the international calendar (I=10 ), then the points at stake would be 10 * (1 - 0.8205) = 1.795

so, If France were to meet Armenia and win, they would get 1.8 points. But if they meet Belgium and win, they would get 5 points in that friendly match...


BTW, not sure whether FIFA will continue to do it's absurd rounding of points or not! :)
User avatar
jaydeep
Moderators
Moderators
Posts: 23792
Joined: Wed Aug 18, 2004 8:59 am
Please enter the middle number: 1
Location: India

Re: Football: Indian National Team news ...

Post by jaydeep »

Thanks Jay and Kujo for taking extra pain to understanding and then explaining to us about this new ELO points system ... :notworthy:
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

Thanks Jaydeep!

Few things for Jay:
1. I confirmed the 868 - by actually assigning the Pseeding values for all teams, based on their ranks prior to the world cup. As for your question on linear distribution of ELO ratings - it is very relevant. The true strength of a team would be based on the difference in ELO points between it and the next placed team in the rankings. If this were to be a constant 4 points, that means we are glossing over some of the team's strengths... unfortunately, that's what just happened....

2. A total of 372 ELO points (infusion / inflation) were added to the total base ELO points(255588), after the worldcup was concluded. Which means an increase of 0.15%. As years progress, this will continue to increase the total ELO base points and we may need to adjust the "I" value, to catch up to inflation....

3. FIFA is now patting on its back for a job well done, by ranking France as top team in the just released rankings (despite a major overhaul on how rankings are computed!). France got a whopping 150 additional ELO points for their worldcup performance. Four years from now, France might continue to be ranked number 1, despite an ignominious exit in the first round of Worldcup in Qatar. While Germany might win the worldcup and still be ranked number 5. At that time, they (if not FIFA, at least the fans) will wonder why / how did this happen?

Once you go down, the climb up the rankings is WAY harder!!
User avatar
jayakris
Moderators
Moderators
Posts: 34757
Joined: Mon Dec 16, 2002 7:24 am
Antispam: No
Please enter the middle number: 5
Location: Irvine, CA, USA
Has thanked: 10 times
Been thanked: 1 time
Contact:

Re: Football: Indian National Team news ...

Post by jayakris »

Whoa, that was what I was fearing. That they may have just managed to get good rankings this time, but it might not work the next time around. Then what are they going to do? I will study this more. I need to get a clearer sense of the importance of the total base points.

And thanks for confirming that my guesses behind that 868 were right...

By the way, I was surprised that S.Korea ended up as low as they did. With Germany being up there as #1 in the last rankings, I thought Korea would get something big for beating them, but ELO didn't seem to help.
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

South Korea had two losses in the group stage - which amounted to a negative 73% of points available (50). And their big win over Germany gave a positive 69%. So the net result was a -4% of 50 points i.e) -2 change in their ELO points... Although it shows a net change of -1 in the official ranking points ....

This could be because, the point differences in the initial ELO seeding of teams was all even (separated by 4 points each) - whereas in reality, there should have been a much wider gap between Germany and Korea.... For example, before the new ranking there was more than 1000 point difference between them, while in the new one they had 212 point difference only...!!
User avatar
jayakris
Moderators
Moderators
Posts: 34757
Joined: Mon Dec 16, 2002 7:24 am
Antispam: No
Please enter the middle number: 5
Location: Irvine, CA, USA
Has thanked: 10 times
Been thanked: 1 time
Contact:

Re: Football: Indian National Team news ...

Post by jayakris »

kujo wrote: Wed Aug 22, 2018 10:10 pmThis could be because, the point differences in the initial ELO seeding of teams was all even (separated by 4 points each) - whereas in reality, there should have been a much wider gap between Germany and Korea.... For example, before the new ranking there was more than 1000 point difference between them, while in the new one they had 212 point difference only...!!
That was my guess, but I didn't want to bias you before you looked at it. Their win against Germany should have given them so much more points than the two losses against teams ranked above them. In fact I saw somebody predicting earlier with a calculation using the points of the independent ELO ratings (that existed earlier) that S. Korea might move up to around #27 or something on that rating. That was probably a bit too much, but they deserved to move up at least to the 35-40 range. Korea is one team that got totally screwed. In fact, teams like Egypt dropped badly and fell behind teams that were inactive who might not be as good as them. All quite unfair, but people haven't figured things out well enough to complain, and so FIFA got away with murder!

Again the issue is with using a linear scale. I thought a steeper drop of points per ranking spots were needed in the first 10, next 20, next 50 and the next 100. Basically a nonlinear drop. They could have come up with a nonlinear scale similar to what was in the independent ELO ratings that existed earlier.

I find that the world cup matches caused a nonlinear curve at the top now (in the first 40 ranks) where the points plotted against ranks show that the new curve has risen above the Pseed points curve. But seeing that the friendlies between India, Kenya, TPE and NZL hardly made a blip of ranking changes among them, I can see that moving up at the bottom is extremely hard, like you said!

I think this is pretty screwed up. I won't be surprised if FIFA drops this within a year or two and goes to something else. Or maybe they would do a re-curving of points (again preserving the ranks) for a reset of the ELO. I am guessing that ranking changes will be minimal month to month from now on. Am I right?

There lies the problem I have always felt with ELO (or with my understanding of it). We simply do not play enough football matches for ELO to work. I think a team needs to play some 50-60 matches for their rankings to move up by say 20 spots (i.e, get around 10 odd matches against teams that are significantly higher in rankings, say by 40-50 spots, so as to get 4-5 big wins, which is all tough to schedule). And that would take say 4 years. Over such a period, a team's quality could become substantially different. That is, ELO could be simply too slow in responding, for it to be used in football. If teams play 30 matches per year, it would be responsive enough to match the "quality changes" that happen in a team. That is my hunch. Again, am I right?
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

All items you mentioned are on point Jay. Working on a small data analysis to confirm those thoughts /intuitions....
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

The issue with assigning initial ELO ranking points linearly (seeding) based on existing FIFA team ranks.

1. What was used is a linear scale – i.e.) start at 1600 for the top team and reduce by 4 points for the next team, and so on. If you want to visualize that, it looks like this:
We plot how many teams are within each range of 100 points - about 25 in each group. The gap between a top team and a good team is not much in terms of points.
Attachments
seededELO.jpg
seededELO.jpg (46.64 KiB) Viewed 3092 times
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

2. But what was the points distribution before this new ranking was put in place? Here is the visual on that:
As you can see, this looks like an exponential distribution, with quite a few teams bunched up in the lower values, while the long tail is seen for the top ranked teams...
Naturally, the gap between a top team and a good team is quite high here.


Not that these are accurate reflection of team strengths - as folks used to complain about the old ranking system as well. But, it makes sense to see bigger gaps between a top team and a good team - specifically see Korea and Germany.
Attachments
OldPoints.jpg
OldPoints.jpg (46.23 KiB) Viewed 3093 times
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

3. The only other sport which has been using ELO ranking, is chess. If you look at Chess and ELO, there are studies out there, that show the ELO points difference between players will predict the outcome of a match very closely (95% Confidence Interval lines are tight around the expected outcomes).

4. Chess has 10s thousands of FIDE ranked players and I pulled data on all to plot the below chart. As you can see, it is a normal distribution and assuming these ranks correctly depict a player’s strength – we should expect a similar distribution for the FIFA ranking of teams as well. This is a reasonable assumption considering point 3 above. A bunch of teams in the middle group while lower ranked and higher ranked teams are spread out over wider range of points….
Attachments
chess1.jpg
chess1.jpg (44.8 KiB) Viewed 3092 times
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

5. Now the question is, what was the impact of the Worldcup matches (and some minor matches that happened in the July time frame) over this initial uniform distribution of ELO points? Below chart shows the latest ranking data and as you can see, a long tail is beginning to develop for the higher ranked teams….

I suspect, as more matches are played between teams, we will discover their true strengths and will end up either in a exponential distribution or a normal distribution of ELO points - rather than the initial uniform distribution that was wrongly used for seeding teams with ELO points based on ranks....
Attachments
afterWC.jpg
afterWC.jpg (35.92 KiB) Viewed 3091 times
User avatar
kujo
Authors
Authors
Posts: 3040
Joined: Fri Jun 18, 2004 11:26 pm

Re: Football: Indian National Team news ...

Post by kujo »

jayakris wrote: Thu Aug 23, 2018 1:34 am Korea is one team that got totally screwed. In fact, teams like Egypt dropped badly and fell behind teams that were inactive who might not be as good as them. All quite unfair, but people haven't figured things out well enough to complain, and so FIFA got away with murder!

Again the issue is with using a linear scale. I thought a steeper drop of points per ranking spots were needed in the first 10, next 20, next 50 and the next 100. Basically a nonlinear drop. They could have come up with a nonlinear scale similar to what was in the independent ELO ratings that existed earlier.
Egypt was treated fair in the current setup - considering their world cup performance. They had no business, losing to two teams that were ranked 22 and 25 spots below them (Saudi Arabia and Russia respectively)!! Also, if FIFA had done a non-linear ELO scale initially, the drop in points would have been even more! So, they are lucky to have escaped with a smaller drop in points....
desidividend24
Member
Member
Posts: 7
Joined: Wed Aug 22, 2018 4:53 pm
Antispam: No
Please enter the middle number: 5
Contact:

Re: Football: Indian National Team news ...

Post by desidividend24 »

Post Reply