Rate of False Conviction of Criminal Defendants Who Are Sentenced to Death
Samuel R. Gross
University of Michigan Law School
Michigan State University - College of Law
American College of Radiology
University of Pennsylvania - Perelman School of Medicine
March 25, 2014
Proceedings of the National Academy of Sciences, 2014
U of Michigan Public Law Research Paper No. 405
U of Michigan Law & Econ Research Paper No. 14-011
The rate of erroneous conviction of innocent criminal defendants is often described as not merely unknown but unknowable. There is no systematic method to determine the accuracy of a criminal conviction; if there were, these errors would not occur in the first place. As a result, very few false convictions are ever discovered, and those that are discovered are not representative of the group as a whole. In the United States, however, a high proportion of false convictions that do come to light and produce exonerations are concentrated among the tiny minority of cases in which defendants are sentenced to death. This makes it possible to use data on death row exonerations to estimate the overall rate of false conviction among death sentences. The high rate of exoneration among death-sentenced defendants appears to be driven by the threat of execution, but most death-sentenced defendants are removed from death row and resentenced to life imprisonment, after which the likelihood of exoneration drops sharply. We use survival analysis to model this effect, and estimate that if all death-sentenced defendants remained under sentence of death indefinitely, at least 4.1% would be exonerated. We conclude that this is a conservative estimate of the proportion of false conviction among death sentences in the United States.
Number of Pages in PDF File: 11
Keywords: false convictions, wrongful convictions, exonerations, death penalty, capital punishment, survival analysis, statistics, criminal law
Date posted: May 2, 2014 ; Last revised: May 13, 2014
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