The more interesting question might be this: Does preseason performance offer us any additional information? After all, if what we’re seeing is simply that better players play better no matter the circumstance, we already can identify these players based on their previous regular-season performance. To look at the matter this way, I created a regression seeking to predict 2007-08 regular-season performance from 2006-07 performance and 2007 preseason performance. Combining the two improves correlation slightly over 2006-07 performance alone, up to an r of .814. Looking at the coefficients on the two variables indicates that preseason Win% is about a fourth as useful as a predictor as Win% the previous season.
