A nonprofit think tank on Monday retracted a widely reported study that linked last year's closing of hundreds of medical marijuana dispensaries in Los Angeles to a rise in crime rates in surrounding neighborhoods.
Santa Monica-based Rand Corp. said in a statement that questions raised after the study was released last month prompted an unusual internal review.
Researchers relied on a commercial crime mapping service, believing it included information from various jurisdictions, including the Los Angeles Police Department. However, that agency did not give data to the service.
"That review determined the crime data used in the analysis are insufficient to answer the questions targeted by the study," the statement said.
The study looked at crime reports for neighborhoods surrounding 600 dispensaries in the 10 days before and 10 days after Los Angeles officials shuttered the pot clinics last summer after a new ordinance went into effect. The analysis showed crime increased about 60 percent within three blocks of a closed dispensary compared with those that remained open.
The report found that the further away from the clinics the less crime there was.
The Los Angeles city attorney's office called the study deeply flawed and demanded the retraction. Rand pulled the study from its website earlier this month.
"The city attorney's office believes that retracting the study was the right thing for Rand to do and we are pleased they were receptive to our concerns regarding the study's flaws," said city attorney spokesman Frank Mateljan. "The public interest and public safety is always better served when we use accurate and credible information."
Rand researchers plan to conduct a new analysis when they have adequate data.