Sunday, June 11, 2006

Basketball Sabermetrics

In honor of those who are more fixated on the NBA Finals than the World Cup, I continue my spate of recent basketball-related commentary. Be sure to read The NBA's Secret Superstars, an article by David J. Berri, an economist who has brought the field of sabermetrics, traditionally associated with baseball, to basketball. Berri and his colleagues developed an algorithm which incorporates every facet of an individual player's performance as a contribution, positive or negative, toward a victory. His resulting model calculates the "wins produced" by every player in the league.

Thusly he determines a player's real value to his team, and in doing so, finds out which players he says are overrated and underrated. Furthermore, by adding up the wins produced by each player on a team, Berri has a forecast for that team's performance in the standings. His model has been validated as a pretty accurate predictor, with an average difference of only 2.3 wins (for 82-game seasons) for a team in the 10 seasons he has been doing this.

Berri's conclusions match up with empirical observations. Multi-dimensional players like Michael Jordan and LeBron James have high numbers of "wins produced" under his algorithm, while overrated shooters like Allen Iverson and Carmelo Anthony have low scores. Tellingly, vital role players like rebounding extraordinaire Ben Wallace also produce a high number of wins in Berri's model, proving what most fans know at heart: winning teams excel at all aspects of the game, not just scoring. Taking this a step further, Berri concludes of Game 1:

...why do I think [Dallas center Eric] Dampier and [Miami forward Antoine] Walker were vital to Thursday's outcome? Dampier scored only eight points, but he was efficient: making three of four shots and adding seven rebounds. Walker, on the other hand, scored an impressive-seeming 17 points, but he took 19 shots and turned the ball over an astounding six times in the loss.

Relatively straight-forward observations aside, I think Berri's model could be an effective way of evaluating the contributions of lesser-profile players to their teams. Maybe it's time for a Bill James-like analysis of strategy and statistics in basketball?

1 comment:

Anonymous said...

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