Friday, January 10, 2014

Early marijuana use and educational outcomes

Marijuana use is getting more and more accepted by the public and lawmakers. Indeed, many studies have shown that its effects are no worse that allowed addictive goods such as tobacco and alcohol, that it may in some cases even have a positive impact (foremost example: tolerating consequences of various deceases), and it is not even clear that it is addictive. However, there has been little study about the consequences of using marijuana early, that is, by children or teenagers who are still growing up. It is known for a variety of goods that consuming too early can have sometimes dramatic results.

Deborah Cobb-Clark, Sonja Kassenboehmer, Trinh Le, Duncan McVicar and Rong Zhang look at early adopters of marijuana and their educational outcomes. Studying this is not straightforward, as those who smoke early are clearly not a random draw from the population. They likely share characteristics that have an impact of educational outcomes. The study focuses on those 14 years or younger in Australia and how they complete high school and obtain university entrance scores. Marijuana use is obtained by survey, which may introduce additional difficulties, and is linked to an administrative data set on welfare use by their parents. The authors find strong penalties in high school completion from early marijuana uses, and stronger ones for intensive use and for those coming from a disadvantaged background. The impact on university entrance scores is milder, and this applies of course only to those who managed to complete high school. The penalty for welfare-recipient families is, however, dramatically higher in that case. In other words, even if marijuana gets legalized, it needs to be treated like alcohol and tobacco and early use needs to be strongly discouraged with campaigns that can be efficiently targeted toward welfare-recipients.

Update: An email correspondent tells me I am over-eager to reach policy conclusions given the large endogeneity issue which the authors also acknowledge. I think I was indeed too eager. But I would still pursue this policy. The potential risk appears too large for me.

1 comment:

Anonymous said...

Would love to see placebos that use cigarette smoking instead of weed.