WASHINGTON POST: From 2006 to 2012, monthly marijuana use among high school seniors increased by more than 4 percentage points*, from 18.3 percent to 22.9 percent. If indeed marijuana use were the educational catastrophe that opponents predict, you’d expect to see downward pressure on national graduation rates as more kids took up the habit. But in actuality, the opposite happened: over the same period, as kids were smoking more, graduation rates jumped 8 percentage points. This should not be at all construed to imply that increasing rates of marijuana use are somehow causing higher graduation rates. Correlation doesn’t equal causation. And these numbers don’t even constitute an argument against the Lancet study findings – it’s perfectly plausible that any negative consequences of marijuana use are too small to show up in a simple national trendline like this. But it’s a useful corrective against the facile notion that “more weed = less graduation.” In reality, there are a whole host of factors that influence graduation rates, from income to demographics and beyond. Marijuana use may indeed exhibit some pull on the graduation numbers at the national level. But this effect, if it exists, is likely dwarfed by all the other factors at play. MORE