2 Comments

  1. JJ

    Hey, I’m a non-math person that’s into NBA stats. I’ve been reading some of Alex’s analysis, which indicates that this stat tends to be pretty good at both predicting and explaining. I downloaded the spreadsheet that goes back to 78, but I’m confused as to how you have the +/- from back then–do you use RAPM to find the values of box score events and then simply use those weights for games that predate plus minus? If so,how does ASPM address defense that the box score can’t account for? It would be great to get a methods article for your particular variant of ASPM. The treemap’s great!

    • DanielM

      ASPM is purely a box-score stat. I used 8 years of RAPM to develop the weights, and then calculated ASPM back to 1978. Likely, the accuracy won’t be as great at that distance from the regression.

      Yes, there is a significant lack of accuracy due to limited box-score data for defense. The r^2 is much higher for offense than defense when attempting to predict RAPM.

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