If a prosecutor or a detective is totally unable to admit they’re wrong in one case, what that tells you is that they will be making dozens and dozens more erroneous decisions, because they’re not allowing new information to affectRead the full Q&A here.
their views…. I think generally speaking it’s difficult for people to admit they’re wrong, and the higher the stakes, the more difficult it becomes. So what you really want to do is educate people that it’s OK to be wrong. It doesn’t mean you’re a fool. It’s not going to be the end of your life.
The primary cause [of wrongful conviction] is mistaken identification. Actually, I wouldn't call it mistaken identification; I'd call it misidentification, because you often find that there was some sort of misconduct by the police. In a lot of cases, the victim initially wasn't so sure. And then the police say, "Oh, no, you got the right guy. In fact, we think he's done two others that we just couldn't get him for." Or: "Yup, that's who we thought it was all along, great call."
The second most common cause [of wrongful conviction] is the misuse of forensic science other than DNA. In most of our cases, DNA [identification] didn't exist at the time of the conviction, so prosecutors relied on other types of forensic science. It could be serology, which was the old A/B/O blood typing. It could be bite marks. It could be fingerprints. It could be other forensic disciplines: tire marks, shoe print comparisons, fiber comparisons [, ballistics]. None of these is bulletproof—some of them aren't even credible—so we see a lot of wrongful convictions stemming from those.
And there are several other very common causes as well. You have police and prosecutor misconduct. You have incompetent defense attorneys. You have jailhouse snitches, who as you can imagine are not the most reliable sources. And you have false confessions. Twenty-five percent of wrongful convictions involve false confessions. Most people can't imagine why anyone would ever confess to a crime they didn't commit, unless they were beaten into it. But these people weren't beaten. They wouldn't even meet the legal definition of coercion. It's just that the [interrogation] methods that are effective for getting confessions from guilty persons are so powerful that they net innocent people as well—particularly innocent people who are juveniles or have some kind of intellectual impairment or mental health problem.
I think what happens is that prosecutors and police think they've got the right guy, and consequently they think it's OK to cut corners or control the game a little bit to make sure he's convicted. The thinking goes, "God forbid a guilty guy go free because of smart lawyering by the defense" or what have you. They're so convinced that they are right that they feel exempt from behaving right. They don't realize that it's wrong to be unethical. And not just because it could convict an innocent person. It's simply wrong to be unethical.