Nate Silver takes on International Football (soccer)

[Lamar_Mundane]

Nate Silver is an American statistician who has a website, often cited here, called www.fivethirtyeight.com. It covers U.S. elections from a statistical perspective, particularly as it pertains to polls and polling. He recently exposed a private polling company as a fraud, based upon a statistical analysis of one poll that they (claimed they) did.

Before that he was the Managing Director of Baseball Prospectus, a website and publisher of baseball analytics. He developed a prediction model of player performance called PECOTA, which is very highly regarded to this day.

He has developed a ranking system for national football teams based upon a complex statistical formula that varies significantly from the FIFA rankings.

Rankings

Objective

The SPI rating is designed to provide the best possible objective representation of a team’s current overall skill level. In particular, the SPI ratings are intended to be forward-looking: They measure a team’s relative likelihood of victory if a competitive match were to be held tomorrow. This concept may differ somewhat from a retrospective or backward-looking ratings system. The SPI ratings are not trying to reward or punish teams based on their past results; rather, they are trying to predict which teams will have the most success going forward.

Here is his laymans terms description, along with the raw formula.

The top 15 according to his formula and (their FIFA rankings.)

1. Brazil (1)
2. Spain (2)
3. England (7)
4. Netherlands (3)
5. Argentina (6)
6. Germany (5)
7. Portugal (10)
8. Chile (17)
9. France (9)
10. Uruguay (25)
11. Ivory Coast (19)
12. Italy (4)
13. Russia (12)
14. USA (11)
15. Serbia (20)

[Jimmy_Chitwood]

I was excited to see this. I’m particularly interested in the part of his team data that incorporates individual’s performances on club teams. I’d really like to see exactly what goes into that calculation.

[TheBoltEater]

I saw this today as well. It’ll take a while to see just how good this formula is; but if I had to bet my house one way or the other, I’d put the money on Silver’s new formula in a heartbeat. Everyone already thinks the FIFA rankings are ridiculous, and Silver’s reputation is pretty great right now.
I wanted to say his reputation was sterling, but I just couldn’t make myself do it.

[ShibbOleth]

I didn’t think that anybody, maybe including FIFA, took the FIFA Rankings seriously. Let’s compare Silver’s rankings with the ELO Ratings, which seem to have more credibility.

ELO Ratings (current top 15) (SPI) (FIFA):

1. Brazil (1) (1)
2. Spain (2) (2)
3. Netherlands (4) (3)
4. England (3) (7)
5. Germany (6) (5)
6. Italy (12) (4)
7. Argentina (5) (6)
8. Mexico (NR) (18)
9. Croatia (NR) (8)
10. France (9) (9)
11. Chile (8) (17)
12. Russia (13) (12)
13. Portugal (7) (10)
14. USA (14) (11)
15. Serbia (15) (20)

Other countries listed by Silver but not on the top 15 in ELO:

Uruguay (16)
Ivory Coast (25)

How ELO Ratings are determined:

The ratings are based on the following formulas:
Rn = Ro + K × (W - We)

Rn is the new rating, Ro is the old (pre-match) rating.

K is the weight constant for the tournament played:

* 60 for World Cup finals;
* 50 for continental championship finals and major intercontinental tournaments;
* 40 for World Cup and continental qualifiers and major tournaments;
* 30 for all other tournaments;
* 20 for friendly matches.

K is then adjusted for the goal difference in the game. It is increased by half if a game is won by two goals, by 3/4 if a game is won by three goals, and by 3/4 + (N-3)/8 if the game is won by four or more goals, where N is the goal difference.

W is the result of the game (1 for a win, 0.5 for a draw, and 0 for a loss).

We is the expected result (win expectancy), either from the chart or the following formula:
We = 1 / (10(-dr/400) + 1)

dr equals the difference in ratings plus 100 points for a team playing at home.

[DSYoungEsq]

The United States is over-rated in all three cases. :eek:

[Really_Not_All_That_Bright]

That ELO formula is stupid. It gives the Asian Cup, African Nations’ Cup and Copa America the same weight as the European Championships, which is silly (except possibly in the case of the Copa America).