Ranking football clubs around the globe
There is no official world ranking of club football the way there is for national teams. We built one by taking FIFA's ranking procedure and pointing it at club results from more than 200 countries.
Why adapt FIFA's procedure?
FIFA published its first world ranking of national teams in 1993, and it has been under scrutiny from fans, media and domain experts ever since. Most of the criticism lands on the calculation itself, and on the gap between perceived quality and published rank: Belgium's arrival at number one in November 2015, on the back of a single major tournament between 2003 and 2015, is one example among many. In June 2018 FIFA replaced the scheme with an adaptation of the Elo rating.
There is a second problem, easy to overlook. National teams play only a handful of meaningful matches a year, if that. Ranking anything on so little data is hard before the formula is even chosen, which raises the question of whether the oddities come from the method or simply from the thinness of the record.
So we pointed the same scheme at club football, where there is no shortage of matches. The ranking here is not an attempt to say definitively who the best clubs in the world are. It is a test of how well the method holds up when you finally give it enough data.
FIFA's procedure
The current version, introduced after the 2018 World Cup, is Elo at heart:
I, the importance factor, weights matches by what is at stake: 10 for official friendlies and 5 for unofficial ones, 15 for Nations League group matches and 25 for its play-offs, 25 for World Cup and continental qualifiers, 35 for continental finals before the quarter-finals and 40 from there, 50 for World Cup matches before the quarter-finals and 60 from there.
W is the result for the home team: 1 for a win, 0.5 for a draw, 0 for a defeat, 0.75 for a win on penalties and 0.25 for a defeat on them. We is the expected result:
where dr is the rating difference between the two teams. For the initial seeding, teams were spread evenly in four-point steps from 800 to 1600 according to the ranking published on 9 June 2018.
Caveats
Classical Elo is zero-sum: what one team gains, the other loses. Say a 1300-rated side plays a 1500-rated side in a continental qualifier (I = 25). The weaker side's expected result is 0.32, so a win takes it to 1317 and the other down to 1483.
FIFA's version is not zero-sum. Teams that would lose points in knock-out matches lose none, which protects the rating of sides that go deep in a tournament, and slowly inflates the pool of points, lifting the overall mean over time.
The club version
Only the importance factor needs changing. We set I = 10 for domestic league matches, 15 and 25 for Europa League and Champions League qualifying rounds, 35 and 40 for Europa League matches before and from the quarter-finals, and 50 and 60 for the Champions League on the same split. South America's equivalents are treated the same way. In the remaining confederations the Champions League equivalents are weighted at 35 and 40, because they are not as competitive.
Other rankings
This is far from the only football ranking. The official one in Europe is the UEFA club coefficient, used for seeding the Champions League and Europa League; the AFC and CAF publish their own.
clubelo.com rates every UEFA club with the Elo system, a formula simple enough that it has spread from chess to the NBA, the NFL and tennis, and to national teams as an unofficial counterpart to FIFA's. The Euro Club Index is Elo-related too, and comparing where it and clubelo disagree is worthwhile in itself.
footballdatabase.com publishes a worldwide Elo ranking with its own methodology, and clubworldranking.com takes a different route entirely, adapting the ATP ranking procedure from tennis.