When medical marijuana dispensaries close, crime rises in the surrounding neighborhood when compared to areas where dispensaries are allowed to remain open, according to a new RAND Corporation study. The findings challenge the common wisdom that marijuana dispensaries promote criminal activity.

Studying crime both before and after a large number of dispensaries were shut down in Los Angeles, researchers found that incidents such as break-ins rose in the neighborhoods of closed dispensaries relative to dispensaries allowed to remain open, at least in the short term.

In the blocks with the closed dispensaries, the study observed crime up to 60 percent greater than comparable blocks with open dispensaries, but the effects were not apparent across a wider area.

Researchers say the crime detected near closed dispensaries relative to open dispensaries may be caused by factors such as a loss of foot traffic, a resurgence in outdoor drug activity, a change in police efforts such as fewer nearby patrols or a loss of the on-site security provided by dispensaries.

Sixteen states and the District of Columbia have laws allowing medical use of marijuana and at least a half dozen states are debating whether to approve such use as well. The proliferation of medical marijuana dispensaries in places like Los Angeles and Denver has created concerns among police and neighborhood activists that the outlets attract crime and create a public nuisance.

RAND researchers examined crime reports for the 10 days prior to and the 10 days following June 7, 2010, when the city of Los Angeles ordered more than 70 percent of the city's 638 medical marijuana dispensaries to close. One of the principal reasons behind the city's effort was to limit dispensaries because of the presumed connection to crime. Researchers limited their analysis to 10 days because court challenges prompted some closed dispensaries to reopen.

In addition to examining crime around closed dispensaries, researchers also collected details about crime during the same period near dispensaries that did not close and dispensaries in surrounding communities such as West Hollywood, Beverly Hills and unincorporated areas of Los Angeles County.

The information allowed researchers to analyze crime reports within a few blocks around dispensaries that closed and compare that information to crime reports for neighborhoods where dispensaries remained open. In total, researchers examined 21 days of crime reports for 600 dispensaries in Los Angeles County—170 dispensaries remained open while 430 were ordered to close.

The ongoing analysis found that crimes reported near closed dispensaries remained relatively flat while reports of crime near the remaining dispensaries decreased, suggesting a relative increase in crime around closed dispensaries.

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