I don't think that's quite fair, most work I've read the statistical application is perfect (error and correlation coefficients etc. are presented in the development work, not the fan applications). My only beef is with the conclusions surrounding the various "adj" and "rel" factors, and to a lesser extend sh/sv % influencers. The player themselves, QoC, QoT, ZS, score effect, random chance, all interacting, and more importantly all changing. Impossible to model the individual impacts of each on a macro level without considering the others, and there's just never going to be the data to support developing that model. That many of the relationships get smoothed on the aggregate is common sense, in a complex competitive system inefficiencies are going to be corrected before they have a chance to be statistically significant. Player gets better, gets better linemates against better opponents, team gets worse, starts in his end more. No single variable "adj" is going to capture that. By limiting your analysis of contextual factors to what shows up in the ****** macro data you're cutting the usefulness of the good controlled data off at the knees.