About the player rankings

As promised, the Ivy League player rankings made their print-edition debut, so here's a crash course or a refresher, depending on how much you've been reading The Buzz.

The formula, from the book The Wages of Wins is very simple. Points + Rebounds + Steals + .5*blocks + .5*assists - field goal attempts - .5*free throw attempts - turnovers - .5*fouls.

It's based on the very close approximation that the average possession nets the offensive team one point. The value computed by Ken Pomeroy for this season is 1.015 points. So for instance, if a player makes a two-point field goal, his rank simultaneously rises by two for the points and drops by one for the field goal attempt, giving a net difference of +1, which is also the improvement on expectation that the player caused for the possession.

Take a breath before example 2.

If a player goes to the line for two shots and makes one, it's a net zero (plus 1 for the point minus one-half for each free-throw attempt) just like the possession was.

Defensively, a steal is worth one because you're ensuring the other team ends its possession with zero, rather than the expected value of one. And a turnover is just the reverse. A block, on the other hand, is worth just half a point because there's roughly a 50-50 chance that the ball returns to the offense.

On Cusworth: Why is the departed Harvard center still in the rankings? We're measuring contributions, and even with two weeks of zeroes, Cusworth's contributions still tower over much of the league. Expect the center, who graduated after Harvard's first semester, to be passed at a steady rate, but a top-10 finish in the rankings isn't out of the question.

Stay tuned for an experiment, probably after the Penn-Princeton game, where we adjust the ranks not only by team-games-played, but by possessions per game for that team. It will be interesting to see whether that helps Princeton players overcome a natural bias against a team that doesn't have as many chances to make possession-altering plays.

If you'd like any more info on the rankings, please post your question or e-mail me at zlevine@sas.upenn.edu.