Friday, October 17, 2008

Adjusted vs. Unadjusted Stats

Which of these two lists do you think is better at ranking the best goalies since the lockout?

List A:
1. Kiprusoff
2. Backstrom
3. Luongo
4. Brodeur
5. DiPietro
6. Giguere
7. Garon
8. Toskala
9. Legace
10. Lundqvist

List B:
1. Hasek
2. Osgood
3. Backstrom
4. Giguere
5. Gerber
6. Toskala
7. Brodeur
7. Turco
9. Miller
10. Legace

List A is winning percentage compared to teammates. List B is straight-up winning percentage.

I appreciate the criticisms I get with my repeated use of backup statistics, and know that it is not always perfect to compare goalies to their teammates. Some guys get lucky with goal support or have strong/weak backups or play most of the games so their backups play a small sample size against weak opposition. Regardless, I still prefer winning percentage against teammates because I think it does a much better job than the unadjusted number. For every guy who has a very strong or a very weak backup impacting their numbers, there are a couple of Osgoods or Gerbers who are racking up wins because they play on strong teams. Since both stats are imperfect I'm going to pick the one that is less flawed, and to me that is clearly the backup-adjusted one.

There will be special situations that arise (say, for example, Dominik Hasek was your backup goalie), but in that case we just need to take notice and adjust for it, like we often do with hockey statistics (e.g. point totals of wingers playing with Crosby, plus/minus numbers on Detroit, save percentages on the Minnesota Wild, etc.). I don't think that is so dangerous.

This is a bit of a pre-emptive post, I have been working on an evaluation of post-lockout goalies in response to Bruce's study which is coming shortly, and as per usual I am partially relying on teammate-based statistics.

2 comments:

Bruce said...

This is a bit of a pre-emptive post, I have been working on an evaluation of post-lockout goalies in response to Bruce's study which is coming shortly, and as per usual I am partially relying on teammate-based statistics.

CG: I look forward to it. While in general I think backup stats pale into meaningless when they play single digit numbers of games, I look forward to such teammate- based statistics such as goal support. e.g. New Jersey Devils, currently 30th and last in the NHL with just 6 GF in 4 GP, yet somehow sporting a 3-1-0 record. No doubt that's all about shot prevention, what? ;-)

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