The independent think tank RAND Corp. issued a rare public retraction Monday morning, pulling a controversial September study which found that closing L.A. dispensaries increased crime sometimes by as much as 62 percent.
The publication of “Regulating Medical Marijuana Dispensaries: An Overview with Preliminary Evidence of Their Impact on Crime” drew the ire of law enforcement officials. RAND said a post-publication review found that the study did not include key crime data from the Los Angeles Police Department.
An internal misunderstanding about the crime statistics, which come from a third party called CrimeReports, caused the error, said Debra Knopman, a RAND vice president. The text of the original study hinted at trouble:
“According to CrimeReports, its software is used by more than 700 law enforcement agencies across North America. During our study period, the LAPD subscribed to this service, allowing us to extract data on crimes by type, day, and city block. The LAPD no longer uses CrimeReports, possibly because it is launching its own mapping system. During our time period, we compared the data from CrimeReports with those publicly available through the LAPD’s website. The data correspond very closely. However, the data provided by the LAPD are only available for four crime categories (versus thirteen categories from CrimeReports) and are not available for jurisdictions that neighbor the City of Los Angeles.”
But even “that's not correct,” said Knopman. Exactly how it isn't correct, she could not say.
It could be several months before researchers run another study, presumably with voluntary data from the LAPD. Knopman said she had no experience with the validity of LAPD crime statistics, but RAND will post the raw data and the models so anyone can fact-check the report.
“We really want full transparency on this,” she said.
Speaking of full transparency, Legalization Nation asked Knopman exactly how the misinterpretation made it through internal peer review .
“That's a really good question,” she said. “It's the subject of further review.”
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