The critics call the data “inconclusive,” which is another way of saying we’re not yet ready to agree with the findings contrary to our longstanding position. I’d recommend reading the entire article:
What gets little notice, however, is a series of academic studies over the last half-dozen years that claim to settle a once hotly debated argument — whether the death penalty acts as a deterrent to murder. The analyses say yes. They count between three and 18 lives that would be saved by the execution of each convicted killer.
“Science does really draw a conclusion. It did. There is no question about it,” said Naci Mocan, an economics professor at the University of Colorado at Denver. “The conclusion is there is a deterrent effect.”
A 2003 study he co-authored, and a 2006 study that re-examined the data, found that each execution results in five fewer homicides, and commuting a death sentence means five more homicides. “The results are robust, they don’t really go away,” he said. “I oppose the death penalty. But my results show that the death penalty (deters) — what am I going to do, hide them?”
Hide them is exactly what many criminologists intend to do. I spent a great deal of time in academia studying capital punishment and the conventional wisdom there is that the death penalty has no deterrent effect. Most criminals are irrational and don’t contemplate capture, let alone their punishment if caught, tried and convicted.
It seems to make sense, and because the majority of criminologists and law professors that teach at the universities personally oppose capital punishment, that view is most likely the one to prevail.
The only evidence they have is the comparison of homicide rates between the states that use the death penalty and the ones that don’t. But because each state in the union is uniquely different it’s hard to say how much of an influence the penal code has on criminal behavior.
Capital punishment has always been looked down on, hence the “inconclusive” label for these studies. Liberal law professor and death penalty opponent Cass Sunstein said the data needs “more study” and remarked: “If it’s the case that executing murderers prevents the execution of innocents by murderers, then the moral evaluation is not simple. Abolitionists or others, like me, who are skeptical about the death penalty haven’t given adequate consideration to the possibility that innocent life is saved by the death penalty.”
I don’t know how much more “studying” would need to be done to get the skeptics on board with the majority of Americans who favor the death penalty, but something tells me the Sunsteins of the world will never be persuaded.