Is Law Enforcement More Effective Thanks to Legal Marijuana?

By Paul Fuhr 07/24/18

Researchers examined the impact weed legalization has had on crime trends.

marijuana rally in Michigan

While marijuana legalization remains a contentious issue for many throughout the U.S., Washington and Colorado may have proven that in some aspects it is positive.

According to The Washington Post, researchers at Washington State University have concluded that legal pot has “produced some demonstrable and persistent benefit” to police departments.

“Our models show no negative effects of legalization and, instead, indicate that crime clearance rates for at least some types of crime are increasing faster in states that legalized than in those that did not,” researchers said.

Police departments in states where weed has been legalized have apparently been able to focus on other, more serious types of crime, rather than getting bogged down with “low-level marijuana enforcement.”

The Post describes “crime clearance” as when authorities have “identified and arrested a suspect and referred him to the judicial system for prosecution.”

Using available FBI data, the Washington State researchers analyzed the clearance rates in both Colorado and Washington between the years 2010 and 2015. In order to see what impact weed legalization had on crime trends, researchers looked at clearance rates after November 2012 in Colorado and December 2012 for Washington (when weed, respectively, became legal).

The Post did, however, note that both states’ “recreational markets” did not open until 2014. Both states experienced falling clearance rates before weed legalization, showing that “the decline stabilized in Colorado and began to reverse itself in Colorado,” with the Post adding that “no similar shift happened in the country as a whole.”

It wasn’t until legalization that those numbers took a sudden shift in the other direction.

Still, while researchers say the data can’t conclusively prove that legalization was the primary influence on those crime clearance rates, there were no other demonstrable changes in policing strategies during that same time. Instead, researchers can only say that legalization had a “plausible” impact on clearance rates. 

Property-crime clearance rates showed a “dramatic reversal” in Colorado after weed became legal. Researchers also noticed that the clearance rates of other types of crime, such as burglary and motor-vehicle theft, spiked soon after legalization. By contrast, researchers said, national trends remained essentially flat.

“While there were both immediate and longer term differences between states which legalized and the rest of the country in terms of crime clearance rates,” the authors said, “the long-term differences are much more pronounced, especially in Colorado.”

In some ways, that’s all the proof that legalization advocates need to hear when it comes to the efficacy of how police departments use their resources.

“Our results suggest that, just as marijuana legalization proponents argued, the legalization of marijuana influence police outcomes, which in the context of this article is modeled as improvements in clearance rates,” researchers said.

Additionally, researchers found no other crimes in Colorado or Washington upon which legalization seemed to have a negative impact on clearance rates, suggesting that the case for legalizing weed is, from a law enforcement perspective, as remarkable as it is promising. 

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Paul Fuhr lives in Columbus, Ohio with his family and two cats, Vesper and Dr. No. He's written for AfterParty MagazineThe Literary Review and The Live Oak Review, among others. He's also the host of "Drop the Needle," a podcast about music and addiction recovery. More at You can also find Paul on Linkedin and Twitter.