I got letters

May 21, 2011 • 11:05 am

All I can say is that I didn’t make a penny, and that O.J. is now where he belongs.

I worked on many DNA-based cases in the 1990s; my expertise involved making sure that the prosecution used DNA evidence properly in its population-genetic calculations.  The state often got the calculations—the “match probabilities”— completely wrong, biasing the data against the defendant.   (A “match probability” must be calculated when the defendant’s DNA matches other DNA-based forensic evidence, like blood or semen at the crime scene.  It involves comparing the defendant’s genotype with that of a “random” sample of the population, calculating the probability that the defendant-forensic match could have occurred just by chance. This involves principles that are common in evolutionary genetics.)

I ensured that these calculations were correct and, if I had to, took the stand to explain to judges and juries how match probabilities should be calculated. Try telling a jury of regular people, who barely know what DNA is, how to calculate Hardy-Weinberg equilibrium! That was a tough job.

My philosophy here was to make sure that my field was not corrupted by zealous prosecutors trying to secure convictions based on faulty calculations.  Everyone deserves a fair trial, even rich and odious people like O.J.  Almost all the cases I worked on, however, involved poor defendants who could not afford lawyers, and were represented by public defenders who were completely baffled by statistics.  I took money in only the first case I dealt with, here in Illinois, and then decided that my testimony would look less “tainted” were I to work for free. So I did.  But that tactic, of course, was also attacked by prosecutors: they would ask me, when I was on the stand, “Why arent you taking money, Dr. Coyne? Are you on some kind of crusade or something?”

I have always thought that the hardest thing I’ve had to do in my professional life was to get on the stand in a murder trial, trying to deal with prosecutors who were more interested in convictions than truth, and who were determined to destroy my testimony any way they could.  It’s nerve-wracking, for you know that somebody’s life is at stake.  Next to that, a big symposium talk or a grant proposal is a piece of cake!  Fortunately, I didn’t have to testify in the O.J. case.

People ask me how I could work for O.J., who seemed pretty obviously guilty.  My answer is that I wasn’t concerned with his innocence or guilt, but with whether DNA data were presented properly to the jury.  And of course everyone, rich or poor, deserves that kind of expertise.  I worked for free on that case, too, though I could have made a pile.

Have pity on the poor defendants who can’t afford experts!  One thing you quickly learn from this kind of experience is that there is different “justice” for the rich and poor.

62 thoughts on “I got letters

  1. I have absolutely no idea what is going on. Is this a mistake or were you involved in some way in the court case?

    Also, have you only just received this letter dated October ’95?

  2. Yesterday, it was cigars, and today, it’s a letter thanking you for your participation on OJ’s defense team.

    You keep this up, I’ma fall out of love with you.

    ps. I’ll probably still think you’re a genius, though.

  3. http://www.nytimes.com/1994/10/27/us/two-chief-rivals-in-the-battle-over-dna-evidence-now-agree-on-its-use.html?pagewanted=all

    But Dr. Jerry Coyne, a population geneticist at the University of Chicago who opposes DNA typing as court evidence, was angered. “There’s plenty of controversy in the field,” he said. “It just upsets me no end because of the way this was timed. It was carefully calculated to come out right before the DNA hearings for the Simpson case. The only motive I can see is to influence the judge.”

    Ironically, they may have used his public opinion against using DNA typing in court to sway the judge.

    1. Great find to complement and expand on this fascinating post! Thanks for the link.

      Along with the the cautious, the dependability of the testing labs has always been my biggest concern, esp. now in the days of uber-eager deregulation.

      A happy & unforeseen benefit, tho, has been the retroactive use of DNA evidence to reverse wrong convictions.

  4. OJ is yet another innocent black man done over by racist america. That you didn’t actually lynch him is nothing to be proud of.

      1. Done over? He was acquitted despite the almost overwhelming amount of evidence against him.

  5. Well, thank God there are people like you around to get this kind of thing right!

    But what more and more troubles me is the prevalence of bad — not just “bad”, but outright wrong! — statistical analysis in all sorts of fields. Two things amaze me: one, that the editors of respected scientific journals do not have on tap statistical experts to review the treatment of data in all papers submitted; also that they use referees who are apparently as ignorant as pig shit about “doing stats right.”

    The other thing that amazes me is that no one has written a book or website that methodically covers the proper stat treatment of many different kinds of data, including examples of mistaken analyses and explanations of why they are mistaken.

    I know from my own work doing very simple statistical analysis that getting it wrong is easier than falling off a slippery log. Maybe it’s time to require that all stat analyses be carried out by Certified Experts – or something.

    Let’s make one thing clear: I’m personally convinced that O J was guilty as all get out, but better that he go free thanks to prosecutorial stupidity than that he be convicted using using anti-evidence.

    (I’m pretty sure I’ve groused about this topic before, possibly here, so apologies if I’m repeating myself.)

    1. There was enough evidence outside of the DNA to convict him, IMO. There are few things in life that I’ve done “religiously” and one of them was watch the O.J. trial.

      In placing blame for why he was acquitted, I think that the jury probably deserves as much as the prosecution. Of course, there was a lot of evidence that we saw that they didn’t.

      1. I watched the entire thing, too. Probably cost the company for which I worked at the time a million dollars in lost billings, but, you know.

        So I watched for days. And then a month. And then months. I paid attention.

        The jury was out for an hour.

        Straightforward case of jury nullification.

          1. “Jury nullification is about vetoing the law, not the evidence.”

            Indeed, and in the murder trial the evidence handling and control was appallingly incompetent or dishonest. That jury did an excellent job and stood up for real justice, something that rarely happens in the USA.

            In the Vegas trial the jury was clearly bent on revenge and cared nothing for justice. They should all be thoroughly ashamed of themselves as they once again showed that American juries prefer ‘feelings’ to evidence.

      2. This sounds much like the comment made by George Will. Mr. Will opined that if 90% of the evidence was plante3d by the police, the remaining 10% would have been enough to convict Mr. Simpson. This, of course is absolute rubbish. If 90% of the evidence were shown to be planted, who in their right mind would have any confidence that the remaining 10% was credible?

    2. I don’t want to hijack the thread by entering into a long discussion of the Simpson/Brown/Goldman case but there is a substantial case to be made that there was a 4th party present at the murder site, which individual very possibly planted the right handed, extra large, Aris lite glove behind the Simpson house. IMHO, there is virtually no doubt that Simpson was at the scene of the crime so the only question is, what did he do there?

  6. The state often got the calculations—the “match probabilities”— completely wrong, biasing the data against the defendant. I ensured that the calculations were correct and, if I had to, took the stand to explain to judges and juries how match probabilities should be calculated.

    Then kudos to you.

    I don’t know enough about the subject to know if your calculations were correct, but your rationale is spot on.

    Science and its practice entails an ethical honesty that’s not always going to be ‘comfortable.’ Too bad. The ends does not justify the means; the means are the ends. Method, method, method.

  7. “O.J. is now where he belongs”

    Really? Is he in prison or dead right now? Because, that’s where he belongs for brutally murdering two people and leaving his children motherless.

    Can you honestly tell me that you think O.J. is innocent?

    1. He’s in prison in Nevada, which is where he belongs. He was convicted in 2008 on charges of kidnapping, assault, and other felonies, and will be in jail for a long time.

        1. As much as I abhor police brutality, I don’t see how the aggressive but non-brutal arrests of Asa Eslocker and Amy Goodman or even the knee on Matthew Rourke’s (which does seem unnecessary) are anywhere near the severity of the multiple murders committed by OJ. The suppression of democracy seems to be the biggest crime committed by the police here.

          Nor do I see how OJ had any excuse for his actions.

          If you really want to make a point, you could link to any number of stories about police smashing peoples teeth out against the concrete, or worse, but I still think that few acts of police brutality are worse than a multiple murder.

          1. You’re assuming that Simpson killed his wife and her friend. The ‘evidence’ for this is far too slim and far too unreliable. I can make a better case for Fuhrman (yes, former detective of the LAPD, Fuhrman) as the killer than he can make against Simpson.

            1. No one is assuming anything. Simpson killed his wife. That a jury of idiots let him go speaks to their and the prosecution’s profound stupidity.

              1. It wasn’t really the jury’s fault. Between the difference they saw in the evidence compared to the rest of us and the repeated bungling by the prosecution, if you just look at the case from the perspective of one of the jurors, it actually does look more like OJ was the victim of a rather badly constructed police setup.

            2. The problem with the Fuhrman theory is that the detective had a pretty good alibi as he was at an event down in Orange Co. and did not return until sometime after the murders apparently occurred.

              1. Regardless of what you think of Microraptor’s comment, I don’t like this kind of name calling here. Calling someone an “imbecile” is something we don’t do around here; nor is it constructive. If you have a quarrel with his contention, address the contention–not the person.

  8. Can’t disagree with anything you said in your explanatory paragraphs (fascinating–there’s a book in that stuff). I rescind my previous assessment, but am not overlooking the cigars.

  9. “calculating the probability that the defendant-forensic match could have occurred just by chance.”

    Hmm. Is this about the difference between a match to a person who seems totally unconnected with the victim and maybe lives in a different state, versus a match to a person who was (say) the victim’s neighbour?

    The odds of some random person in the country matching the perpetrator may be significant, but the odds of the victim’s neighbour matching are not…

    Or was it something completely different you were telling them?

    1. I’m not a fan of Michael Moore. I believe he twists facts around and uses creative editing to tell his story rather than ‘the’ story. But this time, he nailed it dead right.


      Dammit, we’re America. We’re the good guys. We set the standards. As emotionally gratifying it is to know the bastard was gunned down, unless those SEALs were in mortal danger, it was the wrong thing to do. We have dealt with worse before and we should have dealt with him too.

  10. Dr. Coyne, if you are allowed to say, once you corrected the match probabilities in the Simpson case, were they exculpatory? Or, were the match probabilities still damning, but not as damning as the prosecution made them out to be in their faulty calculations?

    1. The answer is no, it was just less incriminating. However, I think that is beside the point. The fact is what the jury heard was that the prosecution expert, Prof. Bruce Weir, supposedly a mathematician and statistician incorrectly calculated the probability of a certain blood sample being someone other then Mr. Simpson. Given that all the numbers they heard were computed by Prof. Weir, it is not surprising that they were not convinced by his testimony.

  11. JAC, thanks for your principled, ethical stand. The US criminal trial system really stinks upon examination, and the allowance of paid “experts” always seems like a neon sign for attracting cynical opportunists (putting it nicely!).

    If we really believed in equal justice, we’d have pools of experts who would be expected to serve when called on as in jury duty. Perhaps with some similar per diem, but no more.

    1. I’ll second that! It was news to me that he was doing this public service and it’s even better IMO that he isn’t charging for his expertise. What a great person!

  12. I also want to say thank you for taking your time to make our justice system a little more just.

  13. In an adversarial legal system like the US, everyone has to get the best defense possible (even if they seem guilty). Otherwise, a lot of innocent people will get railroaded into conviction.

    Of course, being rich helps one’s defense efforts greatly. If OJ had been poor, I doubt expert defense witnesses would have been consulted at all.

    Anyway, this is yet another chapter of Dr. Coyne’s very interesting life.

    1. If OJ had been poor, I doubt expert defense witnesses would have been consulted at all.

      Actually, for indigent defendants courts routinely appoint experts, paid
      for by the State, especially in serious cases.

  14. So the truth comes out, Prof. Coyne was the one who discovered the error in Prof. Bruce Weirs’ calculations. Prof. Weir was such an arrogant douchebag on the witness stand that most of observers would have stood up and cheered when his mistake was pointed out to him. Oddly enough, he made a much better witness after admitting to his mistake as he apparently was much chastened and lost much of his previous arrogance. However, he certainly lost much credibility with the jury.

  15. though I could have made a pile.

    for future consideration, in case nobody mentioned it:

    take a standard fee, and donate the proceeds to charity perhaps?

  16. I thought that the defence attorney (Barry Schreck?) used a clever tactic to undermine the DNA evidence that had nothing to do with the probabilities.
    He argued that all the OJ blood spots showed evidence of contamination with the preservative EDTA. That would point towards a scenario where the blood had not come directly from OJ but from a stored sample of his blood (blood is often taken into tubes with a preservative sich as EDTA Or heparin). The blood spots were discovered some time after OJ had been arrested and given a blood sample so it fitted a timeline and story where a bad racist cop (Fuhrman) tried to frame OJ by taking the donated (and EDTA containing blood) and placing some of this at the crime scene.
    I don’t believe this actually happened but it was a good tactic to use when you have a racist policeman as your opponent and strong DNA evidence that needs to be discounted.

    1. Actually, the accusation of blood planting was made against detective Vanatter, not detective Fuhrman. The latter was accused of planting the glove behind Mr. Simpsons’ house.

  17. Thanks for posting this – I find it fascinating.

    A problem with the adversarial system, as you have discovered, is that you’re damned if you do, and damned if you don’t.

    Good on you for doing it regardless.

  18. Jerry, thank you for performing this public service in what are going to b frequently very difficult circumstances.

    The truth is the truth, and it matters. It matters in every case. It matters, whether or not the defendant is guilty, and it matters, whether or not the defendant gets off.

    The truth matters when there’s a murderer on trial and it matters when there’s an innocent man on trial, and the only people who get to decide which is which is the jury. You would be doing the right thing to appear and give your expertise about the evidence whether it was OJ or not.

    What some of those prosecutors may fail to appreciate is that your actions help to preserve the ability of DNA evidence to help secure convictions in the future.

    If they get away with abusing it, DNA evidence will end up being shown to be unreliable (since it will be misused, it will help to secure convictions when it shouldn’t and some of those will be later overturned with other evidence).

  19. Jerry,

    I’m SO impressed with your principle of not accepting money for expert testimony. Your professional and personal ethics are of the highest order.

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