Yeah, they mentioned looking at frequency of use (number of days), but not the context of use (before running vs. before couch-potatoing vs. before sleep) nor the amount per use (0.1 gram? 1 gram? A KILOGRAM!?) nor the method of use (bong? bowl? vape? edibles?).Also worth considering: The guy who smokes a bowl and works on coding vs. the guy sinking into the sofa sitting through SpongeBob re-runs. The latter is more common, and IQ tends to decline with age regardless of environment. Did they control for that?
Too many unknowns in general. We'll be teasing out the details for decades after legalization. I'll probably start reading meta-studies sometime around 2050. Of course, that's if I can still read by then, after all the pot I plan to smoke* in the meantime. So far, I'm the best lab rat for me. Haven't been able to conduct any double-blind studies with myself (still working on developing that schizophrenia), but single-blind studies are going well. I can distinguish between many jelly bean flavors, and between several mainstream psychedelics. *I've gotta get a vaporizer...