National Academy of Sciences Study Shows High Rate of Innocence Among People Sentenced to Death


A study published this week in the prestigious Proceedings of the National Academy of Sciences shows that 4 percent — or 1 in 25 — of people sentenced to death nationwide were wrongly convicted.

The study’s authors concluded that “a conservative estimate of the proportion of erroneous convictions of defendants sentenced to death in the United States from 1973 through 2004 [is] 4.1 percent” – more than twice the percentage of inmates actually exonerated and freed through court action. During this same period, only 1.6% of those sentenced to death have actually been exonerated.

Researchers Samuel Gross, Barbara O’Brien, Chen Hu, and Edward Kennedy found that the main reason so many exonerations are missed is that the cases of inmates who are removed from death row for reasons other than innocence and who are resentenced to life in prison are given far less scrutiny than those who remain on death row. Ironically, inmates who remain under a sentence of death have a much better chance of being exonerated than inmates whose sentences are reduced to life.

“Since 1973, nearly 8,500 defendants have been sentenced to death in the United States, and 138 of them have been exonerated,” explained Professor Samuel Gross of the University of Michigan Law School. “Our study means that more than 200 additional innocent defendants have been sentenced to death in that period. Most of these undiscovered innocent capital defendants have been resentenced to life in prison, and then forgotten.”

The specter of executing an innocent person is one of the principal reasons that the use of the death penalty has sharply declined in the United States. Since the late 1990s, death sentences have declined 75 percent and executions have dropped by half. Eighteen states have now ended capital punishment, including six since 2007. Executions have been indefinitely put on hold by the governors of three additional states.

Last month, Glenn Ford was exonerated and freed from Louisiana’s death row after 30 years. In a case riddled with mistakes, Mr. Ford had been represented at trial by two inexperienced attorneys who were appointed because of where their names appeared in an alphabetic listing of lawyers in the Shreveport Louisiana Bar Association. In Texas alone, Carlos DeLuna, Ruben Cantu and Cameron Todd Willingham were executed, but evidence now strongly points to their possible innocence.

Earlier this year, the United States Supreme Court granted relief to Anthony Ray Hinton, an EJI client on Alabama’s death row who we have long maintained is innocent as well.