## Thursday, September 17, 2015

### Week 3 College Football Math

I'm going to Vegas for the weekend!

I'm going to be doing 3 things: poker, betting on football, and sweating the football I bet on. I've got a little bit of confidence going into the weekend (always a predictor of doom when it comes to Vegas) since for the second week in a row the model outperformed Vegas lines. Once again the model had both a smaller aggregate points error and more games picked correctly.

That's especially interesting this week, of course because I'll be in Vegas and throwing down some cash, but also because the model disagrees with Vegas this weekend in big ways on a few games. For example:

• Cal vs. Texas: Texas is a 7 point underdog, I have Texas favored to win 61% of the time
• Notre Dame vs. Georgia Tech: I have Notre Dame at 61%, Vegas has them as 2.5 point underdogs. This one probably deserves an extra caveat since my model doesn't account for injuries until after those injuries start to reflect game outcomes
• UTEP vs. New Mexico State: Vegas has UTEP as a mere 2.5 point favorite, I have them 84% to win
I'm not sure what that means. Hopefully it means that the model knows something Vegas doesn't, but who knows. Even if all 3 games go my way (or go the other way) while that would be good (or bad) evidence for the model's effectiveness they're still just 3 tiny drips of information in the long march of a college football season.

• A team is shaded green according to their chance to win (darker = better chance)
• I'm experimenting with new names for the Watchability index. I really like the idea behind that number, but the name has never sat very well. I'm currently testing out Expected Game Quality, which I like for its simplicity. Don't hesitate to share comments on the new name or suggestions for other names
• Expected Game Quality (formerly Watchability) is a combined measure of how good the teams are and how likely the game is to be close. Put another way: it's an estimate of how likely the game is to be a close, well-contested game
• This post has more detail on the math behind Game Quality