I'll just reiterate what a great deal of other sensible folks have already said: I think it's quite silly to try and use this study to draw or support any overa

I'll just reiterate what a great deal of other sensible folks have already said: I think it's quite silly to try and use this study to draw or support any overarching conclusion about whether weed should be legal or not. Of course your grades will be affected if you smoke when you ought to be studying. Of course your grades will be affected if you drink when you ought to be studying. Of course your grades will be affected if you study (the wrong course material) when you ought to be studying. Basing decisions about legality and restraints on individual freedoms on things like average academic performance reduces individualism and pushes, by default, a sort of nationalistic view. "No you may not do X because it makes you a less valuable asset to the nation state, and you are meant for nothing more than service to the nation state." Even innocent studies like this hide dangerous potential ideologies and subterranean reductions of individual freedom that politicians will try to push.