Thursday, February 28, 2013

Exploring In-Game Win Probabilities [Updated]

This past year we've been working on providing live in-game win probabilities for every FBS game. By this, we mean that given the current situation on the field -- the teams playing, the score, the time remaining, possession, down, distance, and field position -- what are the odds that each time will win?

However the in-game win probabilities we posted this past season were a function only of team strength, offensive and defensive efficiency so far in the game, the magnitude of the lead, and the amount of time left. The obvious glaring deficiency here is that without possession, down, distance, and field position, we're blind to a late-game situation in which a team is driving down the field for a go-ahead score, or when a team with a lead has iced it by preventing the opposing team from ever getting the ball back. Can we quantify that, though? And to what extent are we flying blind by not having this data? Which matters most: possession, down, distance, or field position?

Let's examine our current model, see how it works, test how it's done, and then figure out how to improve it.