Legal Weed May Reduce Crime More Than Previously Reported, Study Suggests
A new report co-authored by a federal US agency official suggests that FBI crime data does not accurately reflect the impact of legalization on crime and that previous estimates were too conservative.
Published on October 19, 2021

Researchers may have already debunked the myth that adult-use cannabis legalization leads to an increase in violent crime, but a new report suggests this research may have actually underestimated the impact of legalization on crime reduction.

As the US cannabis industry has grown from an isolated number of tiny startups into a multibillion-dollar market, researchers have been scouring federal crime statistics to discover whether crime rates have been increasing in legal-weed states. Prohibitionists' fears proved to be completely unfounded, as study after study showed that rates of violent and property crime either held steady or decreased after weed became legal.

But according to a new report by researchers from the US Department of Agriculture (USDA) Economic Research Service and Appalachian State University, these studies may actually err on the conservative side. The report, titled “Smoke and Fears: The Effects of Marijuana Prohibition on Crime,” suggests that these early studies contain measurement errors and assumptions that resulted in an “underestimation of crime reduction from ending marijuana prohibition.”

Many of these initial studies sourced their data from the FBI Uniform Crime Report (UCR), an annual compilation of crime data submitted from individual police departments in every state. But although one might assume that the FBI has an accurate record of all crimes committed in the US, this is actually not the case. Federal law does not actually require state and local law enforcement to submit their data to the FBI, and since the program is entirely voluntary, some police departments decide not to bother with the extra paperwork.

“The voluntary nature of the program creates a missing data problem that adds additional complexity to the use of UCR data for policy analysis,” the study authors explain. To fill in these gaps, the FBI essentially uses average crime rates from nearby areas to replace any data that police departments have failed to report. The researchers argue that this method is highly inaccurate, and instead devised their own “novel imputation procedure to reduce measurement error bias and estimate significant reductions in violent and property crime rates.”

Using their own computations, the researchers concluded that medical marijuana laws [MMLs] “result in significant reductions in both violent and property crime rates, with larger effects in Mexican border states. While these results for violent crime rates are consistent with previously reported evidence, we are the first paper to report such an effect on property crime as well. Moreover, the estimated effects of MMLs on property crime rates are substantially larger, which is not surprising given property crimes are more prevalent.”

“Drug policy in the US is predicated on the notion that there is a causal link between crime and drug usage,” the authors wrote. “Drug policy makers have stated, 'Efforts to reduce the supply of drugs and enforce the laws of the US are focused on decreasing crime.' Accordingly, US drug policy has been largely focused on prohibition in an effort to stem the supply of drugs. As a result, the number of prisoners incarcerated for drug-related offenses rose 10-fold between 1980 and 2000, far outpacing increases in drug-related arrests which more than tripled.”

Although one of the study authors works for the USDA, the report makes it clear that the findings of this report “should not be construed to represent any official USDA or US Government determination or policy.” That said, it is promising to note that a federal researcher is devoting his time and energy to proving that cannabis legalization is a more effective crime-fighting strategy than prohibition.

Other researchers have also linked legal weed to decreased crime without relying on the FBI's incomplete data. A study of street-level crime data from Sacramento, Washington DC, and Los Angeles found no link between pot dispensaries and increased crime, and another study found that crime actually increased in LA when officials temporarily shut down the city’s pot shops in 2017. A study from 2018 also reports that police in legal-weed states actually solve more crimes than cops in states that continue to waste police resources on prohibition. 

Chris Moore
Chris Moore is a New York-based writer who has written for Mass Appeal while also mixing records and producing electronic music.
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