MLS Releases Castrol Index - Thierry Henry Best

Major League Soccer has released its version of the Castrol Index (powered by Opta). While this index is being kept separate from the overall index that tracks the big leagues of Europe, it does at least provide a singular ranking based on game data. If one were to do a quarter pole MVP New York Red Bull's Thierry Henry would be on the short list so him being number one is not a surprise. Steve Zakuani and David Ferreira fill out the top three, and so the impact of their loss is even more apparent.

There are some issues with the Index as constructed right now. Some will be corrected over time, and the other is more significant. First is the issue of playing time, because it is so early in the season it looks like not a single Real Salt Lake player met the minimum playing time requirement and so Javier Morales isn't in the top 100. Removing that adjustment and he would be a top 15 player. Which seems more than right. Sadly, we won't be seeing Morales because of the tackle that broke his ankle and earned Marcos Mondaini a 4 total game suspension.

The larger issue is that the lack of transparency means that we must trust that Opta and Castrol have constructed the point values for each action based on how that action effects a team's chance to win. For this we truly only have trust. In the FAQ they say;

A key factor for all areas of performance in the Castrol Index is in which zone on the pitch the action takes place. Players receive points for each successful pass they complete, but the number of points awarded depends on which zones the ball is passed from and received in. Similarly, misplaced or intercepted passes are penalised depending on how much trouble the mistake is likely to land the team in.

Which seems intuitive, and possibly correct. But we can't know, not without the data being tested. Points systems are inherently flawed when based on a few opinions rather than the data.

Context is also missing as all goals are considered equal.

8)    Are winning goals worth more than other goals?

No, all goals scored are of equal value.

Which we know is not true. Win expectancy changes based on the timing and number of goals (click through Statistical Analysis to go beyond the initial post on the subject). Factoring that bit of knowledge into their data would be a great adjustment, as it would provide a ranking of the best player similar to baseball's win probability added systems.

But this is what we have now, and the Seattle Sounders injury issues are made clear again as two of the top 15 players in the league are out. The monthly nature of the index means that players with very limited time until May are unaccounted, particularly Tyson Wahl.