There was no immediate consensus to explain the drop. But some experts said the figures collided with theories about correlations between crime, unemployment and the number of people in prison.Normally, the heretical hypothesis that tough sentencing actually works is simply ignored, and we post our elephant-in-the-living-room graphic. This time we have something a little different. Note the last phrase in the first paragraph in the quote above. Our old adversary, Berkeley Prof. Franklin Zimring, tries to spin this result into a contradiction of the efficacy of imprisonment.
Take robbery: The nation has endured a devastating economic crisis, but robberies fell 9.5 percent last year, after dropping 8 percent the year before.
"Striking," said Alfred Blumstein, a professor and a criminologist at the Heinz College at Carnegie Mellon University, because it came "at a time when everyone anticipated it could be going up because of the recession."
As the percentage of people behind bars has decreased in the past few years, violent crime rates have fallen as well. For those who believed that higher incarceration rates inevitably led to less crime, "this would also be the last time to expect a crime decline," he said.
"The last three years have been a contrarian's delight -- just when you expect the bananas to hit the fan," said Mr. Zimring, a visiting law professor at New York University and the author of a coming book on the decline in the city's crime rate.
But advocates of the efficacy of tough sentencing do not focus on the number of people in prison or the percentage of the overall population in prison. We focus on sending criminals to prison. If numbers in prison decline because fewer crimes are being committed (in part, at least, because tough sentencing works), we would not expect crime rates to go back up as a result. Tough sentencing has both incapacitative and deterrent effects. The incapacitative effect lingers because the worst criminals, the ones we gave the longest sentences, are still in prison even as overall populations decline. The deterrent effect depends on the threat of punishment, not executed punishment, and it remains so long as sentencing policy remains tough, even though declining crime rates produce a reduction in the number of people actually getting the tough sentences.
If crime rates continued to decline despite a major softening of sentencing, that would be a different matter. Some people are claiming that, pointing to recent trends in a few states. But I do not think we have enough sample size yet to make that case.And, BTW, it is not bananas that I expect to hit the fan in California.