A BUMMER FOR RAND CORP.

Rand Corp. has retracted its study showing that crime increased in
the areas of closed marijuana facilities. But in any case, the study
had addressed a question no one was asking.

Are medical marijuana dispensaries magnets for crime? That question
matters, because the assumption that such facilities are neighborhood
nuisances is propelling a drive by Los Angeles and other California
cities to craft regulations that limit the number of dispensaries and
where they can operate. So when Rand Corp. came out with a study last
month that seemed to arrive at the opposite conclusion, marijuana
advocates stood up and cheered.

The cheering stopped Monday, when Rand retracted the study.

Rand isn't given to sloppy research, which is what makes its
junk-science study so surprising. The Santa Monica-based think tank
examined crime statistics for 10 days before and after June 7, 2010,
when the city of Los Angeles ordered more than 400 illegal
dispensaries to close down, and found that crime increased
dramatically near the closed facilities. Researchers speculated that
dispensaries, perhaps because they employ security measures such as
cameras, might actually reduce neighborhood crime rather than
increase it. Yet that was so counterintuitive that it should have
raised red flags during the peer-review process.

It certainly raised red flags with the city attorney's office, which
pointed out that Rand had no way of knowing whether the dispensaries
it studied actually closed June 7, and that crime might have
increased because going-out-of-business sales drew criminals to the
vicinity. But that's not why Rand retracted its study. It turns out
that researchers relied for their crime data on a websitethat didn't
include statistics from the Los Angeles Police Department.

Rand officials say they'll redo the study after considering LAPD
data. That's nice, but it still won't fix the key problem with the
study design. Even if the analysis had been perfect, it would have
answered a question no one is asking: What happens to crime in the
immediate aftermath of a dispensary's closing? What residents of
California really need to know is: What happens to crime in the long
term after a dispensary opens?

To find out, researchers would have to look at crime near
dispensaries for, say, six months or a year before and after they
opened. That would be hard to do because it would require comparing
neighborhood crime impacts with changes in crime citywide; moreover,
it may be that dispensary owners choose to locate in neighborhoods
that are gentrifying, so changes in crime wouldn't necessarily be
attributable to a pot shop's arrival. But until Rand or somebody else
figures out how to balance all the variables, we'll remain in the
dark about the relationship between cannabis and criminals.