Founded in 1968, the National Institute of Justice is the research arm of the US Department of Justice. It funded a recently released study by Washington State University, Stockton University and the University of Utah. This found that legalising cannabis had little to no impact on violent or property crime. There even seemed to be a connection with a fall in burglaries in one of the two states examined.

Earlier attempts to determine the relationship between legalising cannabis and crime yielded mixed results. In this case, however, researchers used a better methodology: “quasi-experimental, multi-group interrupted time-series design”, whatever that is.

The upshot

The study appeared in the Academy of Criminal Justice Sciences’ journal, Justice Quarterly, on 8 October 2019. It demonstrated that there was no statistically significant change to rates of violent or property crime in Colorado and Washington state; in 2012, they were the first states to make cannabis legal for recreational use. The study concluded that legalising cannabis had “minimal to no effect” on severe crime.

Details of the study

The study employed data from the Uniform Crime Report, courtesy of the FBI, covering 1999 to 2016. This covered crimes of violence, against property, car theft, and burglary but not drug-impaired driving. A comparison was made between Colorado and Washington state and 21 states where using cannabis was illegal for both medical and recreational purposes. After these two states legalised cannabis, there were one-time rises in property crime in addition to an increase in serious assault in Washington: any effect of marijuana legalisation on crime was short-lived. Researchers noticed that burglary decreased in Washington state. This was the one enduring change in criminal behaviour due to legalising cannabis, although just why is unclear. The study’s authors warned that laws on cannabis might exert different effects on different communities.

Dale Willits is a co-author of the study and an assistant professor of criminal justice and criminology at WSU. In a press release, he cautioned that this was a single study, and legalising cannabis was still a “relatively new” phenomenon, but more such studies could allow policy makers to more fully appreciate how cannabis legalisation affects crime.

Fuck you, cannabis opponents

It’s often claimed that legalising cannabis will cause increases in theft and violent crimes. The most famous example of this was the insane 1936 film Reefer Madness. This is, however, evidently untrue. The authors of the study explicitly contradicted claims by the non-profit group Smart Approaches to Marijuana and author Alex Berenson; both oppose legalisation. Other studies adopted “mixed and inconclusive” opinions of the effect of legalisation on crime. Researchers often feel that their evidence was anecdotal, and they covered too brief a period of time. Another recent study showed crime went down by 19 percent in areas with a cannabis dispensary. Doomsday scenarios envisioned by opponents of cannabis have most assuredly not come true. As co-author Willets put it: “I think it will be pretty clear evidence that, at a minimum, the sky isn’t falling.”