I find there is a substantial difference between the intended performance of statistical tools intended to compensate for such things, and the actual performanc

I find there is a substantial difference between the intended performance of statistical tools intended to compensate for such things, and the actual performance of such tools. See also the attempt to filter out "confounding" variables in more normal statistical analyses; I personally believe that the effectiveness of such tools are extremely overstated and overestimated. There is a certain intrinsic circularity to any such tool.