Saturday, January 15, 2011

Negative Football's Top 25

Dissatisfied with Tommy's Top 25, I decided to make my own. Unlike Tommy's list, though, this one is not compiled using a "secret formula" (i.e., Tommy's personal opinion). I will describe the exact formula below.

But first, here is the list:

  1. Barcelona (ESP)

  2. Manchester United (ENG)

  3. Arsenal (ENG)

  4. Real Madrid (ESP)

  5. Chelsea (ENG)

  6. Manchester City (ENG)

  7. Borussia Dortmund (GER)

  8. Tottenham Hotspur (ENG)

  9. PSV Eindhoven (NED)

  10. Villarreal (ESP)

  11. Bayer Leverkusen (GER)

  12. Bayern Munich (GER)

  13. TSG Hoffenheim (GER)

  14. Valencia (ESP)

  15. Atlético Madrid (ESP)

  16. Mainz (GER)

  17. AC Milan (ITA)

  18. Ajax Amsterdam (NED)

  19. Espanyol (ESP)

  20. Internazionale (ITA)

  21. Twente Enschede (NED)

  22. Juventus (ITA)

  23. Heerenveen (NED)

  24. Palermo (ITA)

  25. Napoli (ITA)

Here's how this list was produced.

First, I computed the offensive and defensive power of each team in terms of goals per game scored and conceded, respectively. Then, I computed an overal power by combing the two scores as 60% offense minus 40% defense. (The minus is simply because fewer goals conceded means more power not less.)

Next, I gave each power an adjustment based on which league it is from. In other words, scoring 4 goals per game in Spain might not mean the same thing as 4 goals per game in England.

Here are the adjustments I used:

  • ENG: 0.95

  • ESP: 0.5

  • GER: 0.35

  • ITA: 0.15

  • NED: 0.0

  • FRA: -0.85

These adjustments were produced by finding a best-fit, log-linear (Poisson) model to the results from Champion's League matches, where teams from different leagues play one another. The resulting values do not seem unreasonable.

Finally, I limited each league to the number of Champion's League spots it has. This was needed so that England doesn't dominate the list. But it's also true that the modeling above uses only data from teams in the Champion's League this year, so there is reason to suspect that it is not accurate for the lower teams in each league.

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