MAASTRICHT, Netherlands (Christian Examiner) – Dutch researchers examined the effect of public policy regarding legalization of pot smoking in terms of the impact on college student performance and found marijuana use negatively affected academic ability, especially as it related to math skills.
The principals took advantage of a temporary prohibition of foreigners from cannabis coffee houses (the epicenter of marijuana purchases in Holland) to observe short term effects of pot smoking on groups of students across nationalities before and during the limited duration of the prohibition in Maastricht, Netherlands.
Basically, the city implemented the ban in order to combat drug tourism. Although students were not the intended target, the embargo provided an ideal opportunity for studying the impact of marijuana's effect among the internationally diverse collegian population.
The researchers isolated the impact of the policy on a measure of individual productivity and applied a difference-in-difference approach, a statistical method that mimics an experimental study (randomized blind selection of individuals for a treatment group and a control group) but using observational data (information already in a database that allows comparison of one time period to another).
Looking at 54,000 grades of undergraduates, and comparing those who were banned to those who were not, they concluded banned students had a 5 percent better chance of passing courses.
Weaker students who were banned experienced the highest improvement, showing a nearly 8 percent increase over pre-ban classroom performance.
Moreover, improvements from not smoking pot were five times higher for courses involving math skills.
"The effects we find are large, consistent, and statistically very significant," study co-author Olivier Marie said. "The grade improvement this represents is about the same as having a qualified teacher."
Importantly, these findings come at a key moment, as more than 20 states in the United States authorize medical use of marijuana and four states allow recreational use.