Football Outsiders (or more precisely, FO reader Mike Harris) has started doing playoff prediction simulations similar to those I have been doing here, except based on the DVOA power ratings. Football Outsiders uses extensive play-by-play data for their power ratings. I use just the opposite approach, using only the out come of each game (won-loss, not score) and where the game was played as the basis of my power ratings. I am a frequent reader of Football Outsiders and have a lot of respect for their work. I’ve considered adding DVOA power ratings as an alternate power ranking scheme to my software, and building a win prediction model from the DVOA ratings, but the job thing has kept me pretty busy this fall. So I’m glad Mr. Harris has taken that off my to do list.
I thought it would be worthwhile to publish a side by side comparion. It is very interesting how closely the predictions based on the two power ranking methods compare, although there are some very significant differences. The difference in prediction for the Denver-SD division race is particularly interesting. SD is clearly better based on DVOA; watching the two teams play it is easy to see why. Denver seldom gets any style points for the games they have won this season. Yet my power rating system is more impressed by Denver because they have beaten three team with winning records (New England, Baltimore, Kansas City) while San Diego hasn’t beaten any. And that is the thing about Denver, they consistently find a way to win. San Diego on the other hand found a way to lose to the Ravens, a game they probably should have won. To some extent, I think that wins and losses captures some of the intangibles that DVOA or other statistical measures aren’t able to quantify. I’m not arguing that W-L is a better predictor of future wins than DVOA; rather, I think the two approaches are complementary. Furthermore, I feel a little more comfortable with some of the DVOA-based NFC predictions. In particular, Minnesota is looking very shaky after their fast start and San Francisco’s high power rating this week is an anomaly due to the large variances in my power ratings. The SF bug is something that I know how to fix, but don’t have time to code this season. On the other hand, it will be interesting to see if Dallas and Philadelphia do as well in the playoff race as projected by DVOA.
Very cool, Mike Harris and Football Outsiders, and welcome to the playoff forecasting business.