by Denis O'Regan
With the Superbowl over and every conceivable statistic from the game duly recorded,I though it would be a good time to try to develop a measurement of individual contribution to the game.
I've had an idea about the methodology to use for a couple of seasons,but the appearance on this site of Brian's win probability calculator has made the application much more feasible.
Basically,every point on the field has an average value in terms of the number of points a team can expect to score.Therefore,the point of the snap will be worth say X points and the end of the play will be worth Y.The difference between the two,be it positive or negative will be the 'worth' of the play in terms of increased or decreased expected points.
Passing plays are potentially more interesting than running plays because they can be further broken down into their component parts by taking yards after the catch into account.You could think of the points difference from the point of the snap to the point of the catch being attributed to the passer (with the assistance of the catcher) and those from the point of the catch to the end of the play as belonging to the receiver (with the assistance of the passer).
Overall it's a way of defining individual plays,and therefore individual players contributions to a game in the more readily recognizable currency of game points.It also puts into context plays for big yardage gains on third and long that don't get to the first down marker.
Here's how these calculations look for the two outstanding performers from this month's Superbowl.
Larry Fitzgerald caught 7 passes,his yards after the catch numbers changed the points expectancy for his team by a cumulative 7.7 points.Kurt Warner's contribution on those completions came to a cumulative 3.9 points and incompletions reduced the team's expected points by 0.6.
Combined,the Warner/Fitzgerald duet altered Arizona's points expectation by 11 points.That's 1.4 points per pass attempt.
Pittsburgh's SB MVP Santonio Holmes only combined with Ben Roethlisberger to advance the Steelers expected points by 8 points.Those 8 points were made up from 9.6 yac points,3.1 QB yards points and minus 4.7 points from incompletions and interceptions.Overall Holmes averaged 0.6 points per pass attempt.
Miller contribute a net gain of 3.7 points,Ward 3.1 points,Breaston 4.7 and Boldin(as a result of being the intended recepient of Warner's 100 yard interception return) minus 6.9 points.
Neither side's primary running back contributed positive points to their respective teams points expectation when they ran the ball,although they fared better as pass receivers.
The method can be expanded at look at how whole units perform and looks especially attractive as a way of quantifying the punting unit.
Friday, February 13, 2009
by Denis O'Regan