Study: cannabis legalization helps police solve certain crimes more effectively

A recent study criminology found that the legalization of cannabis in the United States enabled police officers to solve certain crimes more effectively.

Police Quarterly, a scientific journal studying police data in the USA, published on July 4 a study led by David Makin, an assistant professor of criminology and criminal justice at the University of Washington. Peer-reviewed, the study examines the clearance rate, This is the rate of crimes solved by the police, defined as the ratio between the number of crimes solved and the number of crimes counted by the authorities.

The researchers analyzed this rate over an interval from 2010 to 2015, over the whole of the United States and then over the states of Colorado and Washington, both of which legalized cannabis at the end of 2012, and for the crimes of rape, burglary, aggravated assault, violent robbery, theft and vehicle theft.

The number of arrests in Colorado dropped from 175 to 100 per 100,000 inhabitants, and from 120 to 40 in Washington State. In addition, the rate of solved crimes increased slightly, as David Makin says: «Our results do not suggest any negative effects of legalization on the rate of crime solving. Moreover, the evidence shows an increase in some crime-solving rates. Our findings show an improvement in some clearance rates thanks to the legalization of cannabis».

These results are of great significance. The legalization of cannabis is the first major change in American police work since the end of alcohol prohibition in 1933. It's also a godsend for researchers who have been waiting to study this kind of data.