Upcoming EI Symposium: Legalization of Marijuana and its Effects

Edited by Philip Curry and Wesley W. Wilson

Available now on Wiley Online Library Early View, scheduled for print in April 2020. Members login now for full access!

Symposium Introduction

In the last decade, recreational marijuana has been fully legalized in Canada and Uruguay, and, at the time of writing, in 11 U.S. States and the District of Columbia. Legalization has been growing in popularity. A Gallup poll in 1969 found that only 12% of Americans supported legalization, growing to 66% in 2018. A subsequent poll found that people supported legalization due to its medicinal value (86%); to allow law enforcement agencies to focus on other crimes (70%); to allow marijuana consumption to be a personal choice without legal consequences (60%); that it would be a good source of tax revenue (56%); government regulation would make it safer (47%), and, that marijuana was not believed to be harmful (35%).

In opposition, those that oppose legalization are concerned with traffic safety (70%); that marijuana was a gateway drug (69%); that legalization would increase consumption (62%); that there were no social benefits to legalization (60%); that marijuana consumption is harmful (54%); and, that any drug consumption is immoral (43%).

The papers in this symposium speak to most of these issues. Hansen, Miller, and Weber tackle the issue of driver safety (the number one reason given for opposing legalization) in “Early Evidence on Recreational Marijuana Legalization and Traffic Fatalities.” They note that, since legalizing marijuana, both Colorado and Washington have experienced significant increases in traffic fatalities in which at least one driver tested positive for THC. In order to test for causal effects, they employ a synthetic control approach to create control groups that resemble the two states with the exception that marijuana would still be illegal. They find that these synthetic control groups experienced statistically similar rates of both alcohol‐ and marijuana‐related traffic fatalities.

The issue of whether marijuana is a gateway drug that leads to consumption of other, “harder” drugs is at least partially addressed by both Smith's paper “The Effects of Medical Marijuana Dispensaries on Adverse Opioid Outcomes,” and Burkhardt, Chan, and Flyr's paper “The Effects of Recreational Marijuana Legalization and Dispensing on Opioid Mortality.” Both examine the effect of marijuana legalization on opioid overdoses. They both find that fewer people died from overdosing on opioids as a result of marijuana legalization – Smith finds a decrease of 11%, while Burkhardt, Chan and Flyr find a decrease in the range of 20–35%. This would suggest that, at least in the short term, marijuana is a substitute for other substances. Whether it is a complement in the longer term, in other words whether marijuana acts as a “gateway drug,” remains to be seen.

When it comes to the effects of marijuana consumption on the individual and society at large, Krieg and Wright take a look at the effects of easier access to marijuana on performance at college. In “Getting Into the Weeds: Does Legal Marijuana Access Blunt Academic Performance in College?,” they find that when marijuana is legal, students do experience a drop in academic performance once they turn 21 (the legal age for consumption in Colorado). This effect is not the same for everyone, however. In particular, Krieg and Wright find that it is primarily males who are already at the lower end of the distribution who experience this decline in performance, and that it occurs mostly in quantitative courses. In other words, marijuana legalization comes with a cost for economics professors.

Millán‐Quijano does not examine marijuana, but much can be learned from their paper “Internal Cocaine Trafficking and Armed Violence in Colombia,” which examines violence in the cocaine market. Specifically, they consider the effect of price fluctuations in the United States and Europe in the price of cocaine on the homicide rates in the Colombian cities that would serve those markets. They find that a 1% increase in the price of cocaine in the US leads to an increase in homicides in Colombia of 0.545 or 0.747 standard deviations in the Colombian cities that serve the relevant market (the Atlantic regions for the former and the Pacific regions for the latter). A one percent increase in the price of cocaine in Europe similarly leads to an increase of 0.505 standard deviations in violent deaths in the relevant regions of Colombia.

The symposium has two papers that examine the extra‐territorial effects of marijuana legalization. In their paper, “The Cross‐Border Spillover Effects of Recreational Marijuana Legalization,” Cowan and Hao consider the effect of marijuana legalization on crime rates, specifically that of marijuana possession, in border counties of neighboring states. They find that marijuana legalization in Colorado and Washington led to a statistically significant increase in marijuana possession charges in these counties. Meanwhile, Stillman and Zambiasi examine how marijuana legalization affects migration to and from the legalizing state. In their paper, “The Pot Rush: Is Legalized Marijuana a Positive Local Amenity?,” they find that Colorado experienced a slight increase in people moving to the state after legalization with no effect on out‐migration.

The legalization of marijuana is a growing legislative outcome. There are many issues addressed in this collection that are of direct importance to voters and policymakers: traffic safety, crime, cross over effects in other states and on migration. The results presented here suggest that, to the extent that outcomes are quantifiable, the worst fears of marijuana critics have not been realized so far. Yet, there is considerable work to be done on medical and tax consequences as well as more basic research on the normative issues relating to consumer choice and government actions.