The Santa Monica-based RAND Corporation has retracted a recent study that linked the closures of medical marijuana dispensaries throughout Los Angeles to increases in crime.

Released in September, the study “Regulating Medical Marijuana Dispensaries: An Overview with Preliminary Evidence of Their Impact on Crime” found that some areas where dispensaries had closed due to the city’s ordinance regulating such facilities were experiencing heightened criminal activity.

Officials at the think tank said questions raised following the publication prompted RAND to undertake an unusual post-publication internal review of the study. The review determined that the crime data used in the analysis are insufficient to answer the questions targeted by the study, officials said.

The primary issue discovered during the internal review was that the data related to the city of Los Angeles and surrounding areas did not include crime data reported by the Los Angeles Police Department, RAND officials noted.

“This was a rare failure of our peer review system,” said Debra Knopman, vice president of the RAND Infrastructure, Safety, and Environment division. “We take our commitment to quality and objectivity seriously, so we have retracted the study in order to correct it.”

RAND researchers intend to conduct a new analysis once they have an adequate set of crime information and those results will be posted online at www.rand.org. Because that work could take many weeks, RAND officials said they wanted to be clear that the study’s findings cannot be validated at this time.

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