John Lott’s newest piece at National Review Online’s The Corner replying to a piece by Andrew Cohen at the Atlantic starts this way:
As an example, in the Atlantic this past Thursday, Andrew Cohen went after what I have written on the death penalty at National Review Online and in my book Freedomnomics, pushing the claim that “no reliable study by credible researchers has ever found any deterrent effect” from the death penalty. He also gets into the issue of race and quotes John H. Blume, a professor at Cornell Law School and death-penalty opponent, as asserting: “Every credible study has found a statistically significant race of victim effect” on who gets sentenced with the death penalty.
As for the first claim, Cohen relies on a deceased economist who died before he could evaluate my claim and the April 2012 report from the National Research Council (NRC). But even that report, which was edited by two strong death-penalty opponents, contradicts the assertion that “no reliable study by credible researchers has ever found any deterrent effect.” Instead, the report concludes that there are approximately equal numbers of papers showing deterrence as showing no clear effect.
Unfortunately, the NRC report itself is rather biased as it excludes more than half the academic research done. It counts only ten studies (nine were peer-reviewed) that look at all 50 states and what happens when states adopt the death penalty. By my count, 20 peer-reviewed studies and four non-peer-reviewed ones were of the type that the NRC considered — following the 50 states over time to see how murder rates change when states use the death penalty. Without offering any explanation, the NRC just ignored the bulk of the research that showed the death penalty deterred murders.
Politicians, such as those in the Obama administration, simply can’t keep politics out of the National Research Council studies, and they bias reports through whom the government puts on these panels. The Obama administration knows the views of the people they put on the panels.
If indeed they had surveyed all these peer-reviewed studies, they would have found that by more than 2-to-1, these studies found that the death penalty deters murders. . . .