RAND's Research on Marijuana Legalization is Questionable

Confusion abounds following last week's release of a RAND study on the ramifications of legal marijuana in California. In particular, RAND's discussion of rock-bottom prices has growers panicking and the suggestion that use could increase dramatically has opponents chomping at the bit. But, as Pete Guither helpfully explains, the whole thing is just a bunch of wild speculation.

Just look what passes for scientific analysis at RAND when it comes to marijuana legalization:

However, a simple calculation suggests that, if someone believes that marijuana is causally responsible for many crashes that involve marijuana using drivers, legalization’s effect on crashes could be a first-order concern for them. [...]

There is no empirical evidence concerning an elasticity of fatal accident rates with respect to marijuana price, prevalence, or quantity consumed, and, as we have underscored repeatedly, there is enormous uncertainty concerning how legalization might affect those outcomes.

However, 50- or 100-percent increases in use cannot be ruled out; nor can the possibility that marijuana-involved traffic crashes would increase proportionally with use. So it would be hard to dismiss out of hand worries that marijuana legalization could increase traffic fatalities by at least 60 per year…

Nor can we entirely rule out the possibility that legalizing marijuana could somehow cause the earth to stop spinning on its axis, resulting in the incineration of a hundred nations, while others are left buried beneath sheets of ice.

I'm exaggerating, but the point is that when RAND says legalization might double marijuana use and lower the ounce price to $38, they're just babbling because the media is stupid enough to listen. Even RAND admits that their analysis is subject to so many intangible variables as to render futile any effort to quantify legalization's practical impact. The problem is that they went ahead and proceeded to announce various arbitrary computations that sound provocative and mean absolutely nothing.

So, for what it's worth, let's just establish a couple principles that might help sort out some of the confusion here:

1. Marijuana will never cost $38 per ounce in California as long as it remains illegal everywhere else and sells for up to $500. Prop 215 didn't reduce prices by 80% and neither will Prop 19.

2. Marijuana is already way too available in California for any policy change to dramatically impact rates of use. No one is sitting around in Los Angeles waiting for legalization so that they can find a way to buy some weed.

3. If marijuana were a significant cause of traffic fatalities, California's highways would already be stained with blood. See point #2.

Update: Dave Borden has convinced me that I've been at least somewhat unfair to RAND, insofar as a big part of my frustration here results from the way the media presented the research. It's true that the study's authors were careful to explain that there remains considerable uncertainty about the practical impact of legalization. There are issues that I think could have been handled much better, but I wouldn't want to set a standard that prohibits inquiry, simply because so much remains unclear.