“It’s not for a social scientist to say” if that is an acceptable price, he stresses, but he believes policy-makers ought to consider other approaches to crime reduction.
Causation, or Simply Correlation?
Criminologists, including Rosenfeld, are wary of drawing conclusions from the Sentencing Project’s research, however.
“I find the Sentencing Project’s findings suggestive, but we need more facts,” Rosenfeld says. “It’s not terribly definitive.”
Paul Robinson, a criminal law professor at Northwestern University, says the Sentencing Project’s state-by-state comparisons of crime rates and incarceration “tell us nothing, absolutely nothing.”
“Correlation is not cause,” he stresses. “It tells us nothing about cause.”
Robinson believes there are too many variables when comparing different states, and that the complexities defy simple conclusions about the effectiveness of imprisonment. “I don’t think we know enough to decide [whether to build more prisons],” he says.
Daniel Nagin, a criminology professor at Carnegie Mellon University agrees with Robinson, in part. “These kinds of estimates are of limited value,” he says.
Mauer acknowledges that a variety of factors may be behind the stunning drop in crime in recent years, but he says his study serves an important function nonetheless, by challenging the idea that more prisons necessarily mean less crime.
The Sentencing Project study shows “the one thing you certainly can’t do is to assume that building new prisons will give you a substantial reduction in crime,” he says.