Study: 4% of Executed Convicts Are Innocent


There has long been a debate over just how high a percentage of convicted criminals, especially those on death row, are wrongfully convicted. It’s very difficult to properly measure, of course. But a new study that applies a new methodology concludes that at least 4% of those put to death are innocent.

The study, the first of its kind, used a statistical method known as survival analysis. The method is usually used to determine the effectiveness of a medical treatment in reducing mortality rates.

Researchers were thus able to estimate the proportion of death row inmates whose innocence would have been established if they had stayed in prison and thus benefited from resources to defend themselves.

“Even if you are sentenced to death… the chance to be exonerated is much higher if you’re still on death row,” lead author Samuel Gross told AFP.

However, “the great majority of innocent people who are sentenced to death are never identified and freed.”

The researchers used data from the 7,482 people sentenced to death from January 1974 to December 2004.

Among that group, 12.6 percent were executed, 1.6 percent were exonerated, four percent died while on death row, 46.1 percent remained on death row and 35.8 percent were taken off death row but stayed in prison after their capital sentences or convictions were reversed or changed.

Based on the analysis showing a more than four percent error margin in trials, the study said it was “all but certain” that several of the 1,320 people executed since 1977 were in fact innocent.

“Most innocent defendants who have been sentenced to death have not been exonerated, and many — including the great majority of those who have been re-sentenced to life in prison — probably never will be,” it added.

Here’s what we can know for certain: If you actually review past convictions with an eye toward finding inconsistencies and problems, you find them. A lot of them. The reason why more false convictions have been found in Dallas, Texas is because D.A. Craig Watkins established an innocence department that does nothing but review past convictions. There’s no reason to believe that would not be the case everywhere else if only they bothered to look.

Comments

  1. gshelley says

    Many supporters of the death sentence seem to think that somehow, it is only the people that woud never have been executed anyway that are exonerated by new evidence. Other than magic, I can’t see how they can possibly hold that view.

  2. krisrhodes says

    Based on their methods the 4% looks to be a minimum bound of innocents, those that could potentially reach the extremely high bar for exoneration. The real # is almost certainly much higher

  3. Trebuchet says

    Well they were jailbirds for one thing.

    And most likely poor and black as well. That’s deserving of a death sentence right there.

  4. colnago80 says

    Oh, but as the late and unlamented Dominick Dunne once said, most miscreants convicted of crimes they didn’t commit were probably guilty of other or worse offenses for which they were either not suspected or where there was insufficient evidence to convict.

  5. says

    It’s not the first time I’ve heard of this. There are at least a dozen proven cases of this happening. If there are a few among thousands, then there could be hundreds among thousands.

    http://www.deathpenaltyinfo.org/executed-possibly-innocent

    http://www.innocenceproject.org/Content/The_Innocent_and_the_Death_Penalty.php

    “It is better that ten guilty persons escape than that one innocent suffer”
    – English jurist William Blackstone

    “It is better that a hundred corrupt officials (*) not suffer punishment than a single innocent person go free.”
    – The US legal system

    (* – police, judges, prosecutors, forensic experts)

  6. justsomeguy says

    @5: I believe the practice was common about 200 years ago in France.

  7. scienceavenger says

    And most likely poor and black as well.

    And even more likely to have killed a white, IIRC the literature. I’ll bet you can count on one hand the number of executed white assailants who killed a black man.

  8. jaybee says

    I thought the study concluded that 4% of those convicted of the death sentence are innocent, not that 4% of those executed are innocent. One might assume the same ratio holds, but the study didn’t make that claim. The article says that “several” of the 1340 people executed surely were innocent, but didn’t claim 50+ were.

    The full article does say there are confounding issues: that many sentenced to death row end up having their sentences commuted to life, at which point they have fewer options for retrial and less chance for exoneration. On the other hand, those who actually advanced to the death chamber receive the most scrutiny and are thus less likely to be among the ~4% who are innocent.

  9. voss says

    Just sent an email to D.A. Craig Watkins department thanking him for the work he is doing.

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