Four less-than-obvious theories for L.A.’s record drop in crime

The last time the crime rate in L.A. was this low, the Black Dahlia had been only two years in her grave.

The last time the crime rate in L.A. was this low, they were handing out the first-ever Emmy awards (KTLA won).

The last time the crime rate in L.A. was this low …. well, you get the idea.

The mayor and the police chief, Eric Garcetti and Charlie Beck, respectively, were justifiably over the moon this week about the winning streak, 11 years of plummeting crime rates, the lowest overall since 1949.

Both of them credited community policing, community groups and the use of computerized crime data for the laudable numbers.

Some other theories have been floated, some more far-fetched than others, but there’s a master’s thesis lurking in each and every one of them:

• Full prisons. The more people you put behind bars, the fewer criminally inclined are out and about to commit more crimes. Although that seems right intuitively, the numbers don’t necessarily bear that out.
• Recession. Also counterintuitive because you’d expect that poverty would drive people to desperate, violent measures. Researchers are puzzling over why this didn’t happen. Maybe the potential evildoers just couldn’t afford to buy guns and bludgeons.
• Facebook. Someone floated this, evidently facetiously, on Twitter: the idea that social media are so engrossing that people would rather live virtually and legally than commit crimes. There may be some meat to this theory. If they’re playing “Grand Theft Auto,â€� they get to do both, vicariously.
• Legal abortion. This was first floated by the “Freakonomicsâ€� authors -- the correlation between access to legal abortions (and presumably fewer unwanted children, whose lot in life is often a hard one) and a drop in crime. The same numbers showed up in Canada and Australia. I once posed this theory to then-Police Chief Bill Bratton, when he was talking up the drop in crime rates during his tenure. He made the snort of barely contained derision that is usually accompanied by the phrase “knuckleheads.â€� No, he said. That was absolutely not the reason.

Whatever’s making crime diminish, I am, as an Angeleno, delighted that it’s happening. But logic argues that this decline can’t go on indefinitely; there has never been a zero-crime society in human history, insofar as I know.

The difficult part for both Garcetti and Beck will be in tempering their deserved pleasure at the good numbers and getting some talking points and research ready for the inevitable day when the numbers are not so good.

But at least now we know what an achievable goal looks like; exactly how we got there, as Geoffrey Rush’s character says in “Shakespeare in Love�: “It’s a mystery.�

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Follow Patt Morrison on Twitter @pattmlatimes