In a rare move for one of the nation’s most highly regarded research institutions, Rand Corp. on Monday retracted a controversial report on crime around Los Angeles medical marijuana dispensaries after realizing that it failed to include any crimes reported by the city’s Police Department.

Researchers with the Santa Monica-based think tank used crime data compiled by a firm that collects information from about 1,200 law enforcement agencies, including the Los Angeles County Sheriff’s Department, but not the LAPD.

“They made mistakes,” said Debra Knopman, a Rand vice president and director of the infrastructure, safety and environment division. “What we’re wrestling with is how the mistakes went undetected.”

The extraordinary lapse has the esteemed institution closely examining how it reviews its research. The discredited report went through an internal and an external peer review.


“This is not something we take lightly,” Knopman said. “This is a rare event, but it’s happened, and it’s absolutely leading us to take a renewed look at the procedures we follow.”

Rand issues about 300 reports a year, and Knopman said she could recall only one other report that has been withdrawn in the last decade. She said Rand seriously considers all complaints about its research and added, “It’s pretty rare that it leads to a retraction, very rare.”

The study of crime data near dispensaries published last month led Rand researchers to suggest that the stores, which usually have guards and surveillance cameras, may help reduce crime in their neighborhoods.

Lawyers in the city attorney’s office were outraged. They have been struggling to reduce the number of pot outlets and have argued that they are a threat to public safety. Special Assistant City Atty. Jane Usher and Assistant City Atty. Asha Greenberg complained that the report had “critical flaws,” one of which was failing “to obtain or accurately report the available crime statistics.”


“This is the right outcome,” Usher said Monday. “Putting information that’s not credible in front of the public and in front of policymakers does a disservice to everyone.”

Medical marijuana advocates hoped to use the report to dispute allegations that dispensaries cause crime and had blasted Rand for buckling to political pressure when it took the report off its website two weeks ago while it reviewed the criticisms.

The Rand researchers relied on data posted by CrimeReports.com, which they mistakenly believed included LAPD data. Knopman said Rand was not blaming the website. She said Rand reviewers, digging deeply into the data, only recently discovered that it did not include LAPD reports.

Greg Whisenant, the Web company’s chief executive, said he had never spoken with anyone from Rand, but would have told the researchers they didn’t have the data they needed. “I think if they were going to cite us, they probably should have contacted us first,” he said.


He said he could understand how the researchers might have made the mistake, but also said they ought to have noticed the lack of crime reported in Los Angeles as compared to other cities. “I think they should have been able to figure it out by seeing a huge pocket of no crime data,” he said.

The researchers, led by Mireille Jacobson, a health economist, reviewed crime reports from the 10 days before the city’s medical marijuana ordinance took effect on June 7, 2010, with the 10 days after, when at least some of the more than 400 illegal dispensaries shut down.

They found a 59% increase in crime within 0.3 of a mile of a closed dispensary compared to an open one. They did acknowledge that those results were subject to a large margin of error.

Usher and Greenberg criticized the researchers for not relying on LAPD crime data, but also questioned the short time frame and the assumption that dispensaries actually closed.


Knopman said Rand will obtain LAPD data and recalculate the analysis. She said Rand reviewers are still weighing the other criticisms and have not reached any conclusions. “We’re going to take advantage of the chance to have a do-over here,” she said.

Usher said she believes Rand will run up against the problem of not being able to determine whether dispensaries were open or closed in that period. “Without a fixed hand on that data point,” she said, “we’re not able to illuminate any crime trend.”

john.hoeffel@latimes.com