Criminal Justice

Juries Often Get It Wrong


A Northwestern University study of 290 non-capital cases in four cities found that juries arrive at the wrong verdict in about one of six cases, and judges aren't much better. It also found that the errors are more likely to send an innocent person to jail than to let a guilty person go free.

The authors caution that the study's sample size isn't large enough to be extrapolated to the entire country, but they're looking for funding for a broader study.

Via Drudge. 

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  1. What does it mean by “wrong verdict”? Damn, now I have to go read the article, to find out if this is flamebait or not…

    Okay, now I see: “We know there are errors because someone confesses after the fact or there’s DNA evidence.”

    The juries aren’t making errors, they’re just being given insufficient evidence.

  2. The even scarier part is that this study was conducted using samples from cases from between 2000 and 2001. Given the ever growing popularity of the “tough on crime” stance, the ever increasing falsification of evidence / stories by police and D.A.s, I wouldn’t be surprised if it happened more often than one in six cases these days.

  3. I did RTFA and there’s almost no discussion as to what constitutes a “wrong verdict”.

    TFA seems to suggest that the study draws probabilistic conclusions based on the frequency of judges disagreeing with the jury’s verdict. That seems to me to be a pretty weak starting point for claiming the verdict was wrong.

  4. Brandybuck,

    I had the same question. Here’s the answer I found:
    he determined the probability that a mistake was made by looking at how often judges disagreed with the jury’s verdict.
    “If they disagree they can’t both be right,” he explained.

    Just because a judge and jury disagree on the verdict doesn’t mean that they “both can’t be right.” The Judge and Jury may draw opposite conclusions on the credibility of key witnesses, have differing interpretations of what a “reasonable doubt” is, etc. Just because judge and jury disagree doesn’t mean that a factually innocent man is legally convicted.

  5. I hope they get more funding. This is an area that should be studied, as opposed to many of the areas that actually get funding and are studied.

  6. The juries aren’t making errors, they’re just being given insufficient evidence.

    That doesn’t mean they aren’t making errors, it’s just the reason they’re making errors.

  7. Abdul, it seems to me the question is being framed like this: an individual is either guilty of the crime or innocent of the crime. If a judge says a defendant is guilty and the jury says he is innocent (or visa versa), the cannot both be right, because the defendant cannot be both guilty and innocent.

    How could the judge and jury disagree on the verdict and both be right?

  8. I’d like to know how they calculated the probabality of a wrongful conviction. If the judge would have given a different verdict than the jury, that doesn’t tell us whether the jury or the judge was right.

    If the judge is more likely to give a guilty verdict than the jury, this may be because the jury does a better job of protecting the innocent – which is what the Founding Fathers mostly believed.

    If the judge and jury are in agreement, that could mean they’re both wrong.

    I’d like to know more about the study’s methodology. The article is highly uninformative in this respect.

  9. The news article didn’t make sense as noted above. Let’s wait until the paper is posted online, and we can all read it. Or at least skim the abstract and pretend we read it.

  10. Wikijustice?


  11. Here’s the abstract (I can’t get at full text)

    “Average accuracy of jury verdicts for a set of cases can be studied empirically and systematically even when the correct verdict cannot be known. The key is to obtain a second rating of the verdict, for example, the judge’s, as in the recent study of criminal cases in the United States by the National Center for State Courts (NCSC). That study, like the famous Kalven-Zeisel study, showed only modest judge-jury agreement. Simple estimates of jury accuracy can be developed from the judge-jury agreement rate; the judge’s verdict is not taken as the gold standard. Although the estimates of accuracy are subject to error, under plausible conditions they tend to overestimate the average accuracy of jury verdicts. The jury verdict was estimated to be accurate in no more than 87 percent of the NCSC cases (which, however, should not be regarded as a representative sample with respect to jury accuracy). More refined estimates, including false conviction and false acquittal rates, are developed with models using stronger assumptions. For example, the conditional probability that the jury incorrectly convicts given that the defendant truly was not guilty (a “Type I error”) was estimated at 0.25, with an estimated standard error (s.e.) of 0.07, the conditional probability that a jury incorrectly acquits given that the defendant truly was guilty (“Type II error”) was estimated at 0.14 (s.e. 0.03), and the difference was estimated at 0.12 (s.e. 0.08). The estimated number of defendants in the NCSC cases who truly are not guilty but are convicted does seem to be smaller than the number who truly are guilty but are acquitted. The conditional probability of a wrongful conviction, given that the defendant was convicted, is estimated at 0.10 (s.e. 0.03).”

  12. “Instead, he determined the probability that a mistake was made by looking at how often judges disagreed with the jury’s verdict.”

    So when the judge and jury disagree, that always means the judge is right and the jury wrong?

    Incidentally, a judge who “disagrees” with a guilty verdict can issue a JNOV – if she finds that no rational jury could convict. What is the rate of JNOVs in our criminal courts?

    Sloppy article, sloppy post.

  13. Being able to know which verdicts were wrong is half the battle. The obvious conclusion of the study is that juries should be composed of law and statistics professors from Northwestern University.

  14. But of course, as that tool Mitt Romney says, we shouldn’t second geuss juries…EVER. Unless the guilty person is a highly connected GOP operative named “Scooter.”

  15. I would like that option.

    “Would you like a bench, jury, or NW professor trial?”

  16. I would take issue with the idea of an “incorrect” acquittal. Even if the person is guilty of the crime for which they are charged, it is entirely correct that they be acquited if the state fails to make its case properly.

  17. Realizing the potential for abuse, I’ve long toyed with the idea of professional juries. We have impaneled jurors who, can’t do math, don’t understand or believe accepted science, have such poor language skills that they cannot understand testimony, etc. That is where we stand today.

    I am still trying to figure out how the selection of full time, professional jurors could be rationally accomplished. Any suggestion? Any flamings? I have my asbestos jogging suit on, so feel free.

  18. JsubD,

    Pro juries are a bad bad bad idea. I feel you on how incompetent juries are, but they’re still better than the corruption that pro juries would be.

    I think the best reform would be to eliminate voir dire. The attempt to remove people with prejudice results in only people with no opinions being allowed to sit on juries. In other words, all the problems you cite are prerequisites for being a juror.

    Making it tougher to get out of jury duty would also be good. As is oft repeated, juries are filled with people too stupid to get out of jury duty.

  19. I think the best reform would be to eliminate voir dire.

    Think back to 12 Angry Men. How many of those jurors demonstrated knowledge during the deliberations that would have gotten them dismissed during voir dire if the prosecutor had thought to ask the right question?

  20. Warren – No insults? No ranting? An alternate solution instead of vitriol? Damn, you don’t really care about me, do you? 😉

  21. JsD,

    The masochistic said “Hurt me! hurt me!”
    To which the Sadist replied “I won’t”

    *picks lint off chest

  22. Yeah, but 12 Angry Men illustrates a probably incorrect verdict. The more I see it, the more I’m convinced “guilty” was the correct verdict. And that’s without seeing the trial!

    The last time I saw it was a stage prod’n at Teaneck HS with a mixed cast, but they weren’t allowed to call it Twelve Angry Persons as they wanted to. They did, however, change the Yankees game to a showing of Cats, which made no sense because Cats couldn’t be rained out (although it should’ve been, from all I’ve heard of people I knew who saw it). In the cast was student Damon Lindelof, now executive producer of Lost.

  23. Don’t the French have something like professional jurors?

    How about allowing the jurors (or judge, perhaps) to question witnesses themselves rather than relying solely on what the attorneys can pry out of them? There may be some obvious flaw to that I’m not seeing, but always seemed strange that the jurors are expected to find the truth but can’t ask witnesses to clarify or elaborate on important matters that might be confusing or ambiguous.

  24. There may be some obvious flaw to that I’m not seeing, but always seemed strange that the jurors are expected to find the truth but can’t ask witnesses to clarify or elaborate on important matters that might be confusing or ambiguous.

    If there is, I don’t see it either. I seem to recall at least one judge who allowed jurors to ask questions of witnesses. I don’t recall how it ever played out, but I assumed that it was legal. Somebody on this forum will baill me out though. Well, maybe.

  25. Aren’t judges professional jurors?

  26. A good lawyer will make sure the biggest jerkoff idiots in the room get on the jury, and we’re surprised they screw up much of the time?

  27. The thing that bothers me is the remark that this is the first attempt to estimate the reliability of the system.

    If we are going to rely on the accuracy of the law enforcement system, it would be sensible to test it a bit more often.

  28. It’s about time that people know about the corrupt evil system.

    This study is a good first step. I was falsely arrested and convicted and there are a lot of innocent people in jail. There are no research and stuff into things like this. The police and DA’s office are incompetent evil people that lies and falsify reports to cover up their mistakes. They do everything in their power to put innocent people behind jail. Otherwise, god forbid, they would have made mistakes, they might even have been wrong. Better that someone go to jail than anyone of them of the “system” gets the blame.

    Police and people from the DA’s office have personally told me that “they ARE the LAW and they can do whatever the hell they want.” The police even tell me that are writing that they personally witnessed me committing a crime I didn’t do. All I did was said I wanted a lawyer and then they frame me and wrote that I resisted arrest, was on drugs and assaulted a police officer. They are evil evil people. Police and judges lie all the time.

    Juries do not know how corrupt the police and the judges can be and how most things they are told are lies. It is not the jurors’ fault.

    And this was in San Francisco. It gets worse else where.

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