Reality Check

Comparison of three different boxscore metrics (WP48, WS48, PRA) with the real results by using the Top 50 lineups in terms of minutes play during the 2010/11 NBA season until February 2, 2011. The Win% values were calculated by using the Pythagorean Expectation with an exponent of 16.5. The data for the lineups are from The WP48 values are from WS48 values are from and the PRA values are from this blog and can be found under Player Ratings.

Wins Produced, a product of Dave Berri, is the worst boxscore metric when it comes down to predict the success of a certain lineup. The correlation coefficients for both regressions are the lowest. Win Shares is a metric developed by Justin Kubatko ( His metric is doing considerable better than Berri’s Wins Produced.

As a comparison I included PRA, a rating I developed a couple of years ago, but never published anything about it besides some descriptions in German which are already deleted from the internet.

The data:


  1. Crow
    August 20, 2011 at 10:30 pm

    I can understand the line of thought behind not revealing the details of the metric, but… have you extended this test to the full season of data for the top 50 or several years worth? Have you compared the metrics on offensive and defensive splits? Have you considered checking weighted versions of meta-metrics by trial and error or via an optimization exercise? Have you revised the metric? Do you intend to do anything publicly with it in the future? Have you drawn any interest from NBA teams to learn more about it? Do you feel staying private about the details is still your preferred course?

    Just curious. Answer if you wish or not.

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