In 1975, Isaac Ehrlich launched the modern econometric evaluation of the impact of the death penalty on the prevalence of murder with a controversial paper that concluded that each execution would lead to eight fewer homicides (Ehrlich 1975). A year later, the Supreme Court cited Ehrlich’s work in issuing an opinion ending the execution moratorium that had started with the 1972 decision in Furman v. Georgia. Today it is widely recognized that Ehrlich's national time-series methodology is too unreliable to be published in any economics journal.

Over the last few years, a number of highly technical papers have purported to revive the now-discredited Ehrlich finding, again claiming that the death penalty is indeed a deterrent. This work has fared no better than Ehrlich's. In articles published in the Stanford Law Review and the American Law and Economics Review, Justin Wolfers of Wharton and I have reviewed all of these studies in exhaustive and minute detail and found that there is not the slightest credible empirical support for the proposition that the death penalty is a deterrent to murder.