One In 25

That’s how many prisoners on death row are likely innocent, according to a new study. Dara Lind explains:

At least 4 percent of people who receive death sentences in the United States are likely innocent, a new study finds. The paper, in the Proceedings of the National Academy of Sciences, borrows a technique from biomedical research to estimate the number of prisoners sentenced to death who are falsely convicted. The study, by Samuel R. Gross of the University of Michigan and Barbara O’Brien of Michigan State University, finds that at least 4 percent of people who get sentenced to death when they’re convicted would ultimately be exonerated if their cases were closely examined for the next 21 years.

That doesn’t just include current death row inmates: many people who initially get death sentences end up getting their sentences reduced to life in prison. And no prisoner serving a life sentence gets the same level of scrutiny as someone on death row. For this reason, the authors conclude that the rate of false convictions in life-imprisonment cases is probably much higher.

Virginia Hughes elaborates on the study:

Gross and his colleagues collected data on the 7,482 people who were sentenced to death between 1973 – the first year of modern death-penalty laws – and 2004. Of these, 117 were exonerated, or 1.6 percent. But among these, 107 were exonerated while they were still on death row, whereas only 10 were exonerated after their sentence had been reduced to life in prison. This leads to a bizarre situation. If you’re on death row and your sentence is reduced to life in prison, you’re suddenly much less likely to be exonerated than someone who stays on death row.

Steven Hsieh shakes his head:

The study refutes much lower false conviction rates cited by judges and lawyers in the past. Perhaps most notably, Supreme Court Justice Antonin Scalia suggested in 2007 that the wrongful conviction rate is “.027 percent—or, to put it another way, a success rate of 99.973 percent.”

“This would be comforting, if true. In fact, the claim is silly,” Gross writes. “Scalia’s ratio is derived by taking the number of known exonerations at the time, which were limited almost entirely to a small subset of murder and rape cases, using it as a measure of all false convictions (known and unknown), and dividing it by the number of all felony convictions for all crimes, from drug possession and burglary to car theft and income tax evasion.”