FBI admits flaws in hair analysis over decades: Is forensic science all it's cracked up to be?

It wasn’t meant to make a judgment on individual cases but rather the effect of forensic evidence in trials, so your basic statement is clearly false. If randomly sampled cases have similar outcomes while only differing in the presence of forensic evidence, then you can reasonably infer that the effect of such evidence is fairly minimal in a general sense.

Your comment is completely nonsensical. This basically how studies of this sort are done. Even drug studies functions similarly in that if two cohorts are treated the same save a medication being tested, and the control group has the same outcomes as the tested group, then we would likely infer that the medication has no measurable effect. They analogue in this example to your absurd comment from the previous example would be remarking that you don’t know that the medication helped nobody. While that is true, that is NOT what is being tested or inferred.

It’s not a flawed design.

This doesn’t matter. The authors characterization doesn’t change or affect the data. Unless you has some reason why the false positives and false negatives would be different in either group, then this has no impact. Even putting that aside, if juries really responded to physical evidence and demurred when they don’t see it, you would likely see higher conviction rates in those cases.

Explain why his characterization poisons the data or the conclusions drawn in any way? Don’t just hurl childish insults. Explain WHY you think this matters?

I’m sorry. Please state your expertise that makes you more qualified to comment on this or impugn the work of trained experts? The people we are talking about by and large worked for the FBI, so I highly doubt they are ditzy community college grads even given the fact they were wrong in these cases. Please feel free to cite the studies YOU have personally done? I would have to imagine you have expertise int his field given your vehemence on the matter.

A trial isn’t a chemical reaction. You have no idea what you’re talking about – no attempt was made to control for judges, prosecutors, defense attorneys, the fact that different charges may involve different kinds of forensics, etc. This is the problem with trying to gussy up subjective endeavors into “science” – you get pseudoscience backed up by numbers in quantity but not quality because people don’t know what science is.

The author clearly has an agenda, and if he were doing actual science, there would be attempts to counter his biases, replicate his findings, peer-review his methodology, etc. Because he’s a “social scientist” he gets to just write an opinion piece, include randomly picked numbers, and proclaim that it must be science because it has numbers in it.

Why does it matter that people are being sent to prison based on techniques that offer literally zero more scientific credibility than asking defendants to put their hands in a fire and prove they aren’t witches? Again, the only way you could possibly not find this a problem is if you already believe everyone is guilty.

A “trained expert” in hair analysis or arson investigation is no better than a “trained expert” in homeopathy or creationism. I’m more qualified because I don’t believe in magic and they do.

As above, I clearly understand math and science better than these people, which is not surprising, since training in “criminal justice” generally seems to attract the stupid and make them even more stupid.

Your contention is: that it doesn’t matter that people are being convicted on pseudoscience, because according to one terribly designed “study” by a vested defender of the system who doesn’t know what a control group is, they would have been convicted anyway. The burden is on YOU to to explain why you think the entire Anglo-American legal system should be burned down and replaced with the police sending anyone to prison that they feel like, and I have nothing further to defend until you present a case beyond “hey, this guy is a professor of minimum-wage-security-guard studies so you’re not allowed to point out his idiocy!”

Listen, while it’s all well and good to point out the flaws in forensic science, you are missing two key points:

  1. Most of this evidence, and the expertise of these witnesses, can be challenged in court. For example, when some dentist testifies about bite mark analysis, the defense should point out the fact that the FBI deems the science unreliable, and the ADA doesn’t recognize it. Yes, “experts” can have an outsized effect on juries, but that in and of itself doesn’t mean much. Whether it’s hand writing analysis or tire tread matching, the lack of scientific rigor should be, and often is, a matter brought up in court in order to secure reasonable doubt.

  2. Almost every piece of evidence has flaws and lacks strict scientific rigor. Do you really think fingerprint analysis is that much more susceptible to error than stranger cross-racial ID, confessions under intense questioning, police statements, or jailhouse snitches? Probably not, yet we would never, in the case of the first example, tell some rape victim that his/her ID of the assailant was inadmissible due to the lack of scientific rigor and statistical basis of ID’ing strangers of different races.

Of course that doesn’t mean that experts and scientists should just make shit up. However, we need to tread very carefully in thinking that scientific rigor needs to be introduced into every piece of evidence lest it be meaningless or a judicial travesty.

Again, that doesn’t really matter much if there is no reason to expect the two groups to differ much in those respects. It does introduce alternative conclusions, but it doesn’t render the data useless. Moreover, you have done nothing to give credence to those alternatives.

What agenda would that be?

Again, cite evidence people are being sent to jail based on this?

Okay, so I take it you have no expertise or experience to chastise these people.

Clearly you don’t given your comments here.

Wrong. I am saying that there is no evidence, “people died” because of this screw up.

I have better things to do than converse with someone acting like a hysterical person who clearly knows almost nothing about this topic.

So your contention is that no one has ever gone to prison based on a discredited forensic technique?

http://californiainnocenceproject.org/2012/10/fingerprint-experts-mistake-leads-to-wrongful-conviction-in-indiana/

From Indiana, the state where Sommers sourced 60% of his data for whatever reason.

I don’t need to know every panel where the Red Skull has ever appeared to tell you Captain America isn’t real, I don’t need to have the Bible memorized to comprehend that God doesn’t exist, and I don’t need to go to security-guard school to tell a “criminal justice professor” or you that you are defending the validity of wizards sending people to prison.

You’re the one who thinks no one goes to prison based on forensics and everyone who is arrested is guilty. America had a revolution about this once. You should be more more hysterical or move to a country more suited to your personality.

Perhaps you’re using a modern definition of “none”, but in my experience, the exculpatory value of all of these things you listed as having “no scientific validity” is pretty high. A bullet with left hand twist rifling didn’t come out of a gun with RH twist. Clear fingerprints (not electronically matched numerical points of comparison) can sure as hell be verified as nothing like a suspects. (I have no complete whorls on any finger, if you see a clear whorl fingerprint on a surface, it didn’t come from me). Now, positive matching is a bit riskier, but it’s still a big jump from a claim of zero validity.

I’d be really interested in a cite on “crime labs not paid unless they produce a match”

Please cite the post where this was stated.

The exculpatory value of large-scale non-matches may apply to some forms of forensics. The problem is that when juries come to expect it or when the police-controlled crime labs are the ones looking for the non-match, it does more harm than good to defendants. Most people in court can’t afford to independently test evidence.

What shocks me about this story is that I knew that they could do mitochondrial DNA analysis of hair, which can exculpate suspects and can be useful forensic science. I had no idea that visual comparison of hair fibers was being used as evidence at trial. I thought that was just a scam detectives pulled to spook suspects into confessing.

It’s really depressing when the FBI screws something up like this, because they have the resources to get it right. But this isn’t the first time, and it won’t be the last. Once upon a time they made big investments in techniques to determine the precise metallurgical composition of bullets found at crime scenes. At best, such analysis could match a bullet to a particular manufacturer’s batch, which obviously isn’t very useful as evidence of guilt (the box of bullets in his gun safe came from the same batch as the crime scene bullet), but damned if they didn’t try to make use of it.

One false positive error isn’t enough to jump to “literally no value” as evidence though. Hell, if forensic evidence was wrong 25% of the time, it’d still be better than most testimonial evidence. How many different, wrong, descriptions came out of the Michael Brown situation?

I will say, there is likely no escaping the adversarial relationship of investigations. Pretty tough to have double blind studies on real life crime, especially considering manpower. ALL evidence is primarily exculpatory, except for testimonial evidence - at least in theory. You can never be sure someone somewhere doesn’t have the exact same fingerprint as you, or even that you don’t have a genetic twin. Fingerprints and DNA are a lot better than hair and fingerprint analysis, but those are not valueless. If someone is locked up solely on a hair match, something is wrong with the trial, but I’d say more people are wrongly locked up due to crappy representation than mistakes in the value of evidence.

My only experience with crime labs has been Federal, so I was surprised there is any connection to fees for convictions. I think the link is weaker than literal “pay me for my testimony that he did it”. I’m sure no technician gets a split or commission - you can claim they have an interest in more money coming into their institution - and I agree it seems bad enough on it’s face that it shouldn’t be done that way. Anyone in the government with penalty power is in the same situation more or less though. Big legal fines against offenders give money to the government, so should we be worried about that? Maybe every federal judge likes to adjudicate big fines on the basis of more money to their employer.

Sorry for long, stream of consciousness reply… I’m probably done with discussion, I agree there is a lot of room for improvement, but throwing out the baby, the bathwater, and the tub seems overmuch.

But isn’t the possibility of a false positive enough to raise reasonable doubt, at least for that piece of evidence?

I don’t think he was claiming that they are only paid for positives. I think the implication was that a lab that exonerates everybody isn’t going to be getting work for long.

There’s another piece to all of this. Plea bargains.

If a person is innocent, but they’re told that there are lab results that, at least in their mind, may convince a jury, they’re then faced with a terrible decision.

That leads to a question. If someone makes a plea bargain based on questionable evidence, is there any recourse later on?

The labs are only paid when there is a conviction. The article and the study it quotes state it clear as day. I don’t know why people are insisting that this can’t be the case – are you invested in the moral appropriateness of the police and prosecutorial system? You should change that stance if so.

You are severely misinformed about how the American justice system is supposed to work and about the issue with forensics. It’s not “there was one false positive” it’s “there isn’t any basis to walking through the ashes of a burnt-out building and divining if the fire was arson.” These techniques have NEVER been scientifically tested, they are all just based on something some cop came up with one day and are applied in a manner basically equivalent to psychic reading.

Furthermore, a “person who has a 25% chance of being innocent” is called “innocent.” The standard for a criminal conviction is “guilty beyond a reasonable doubt.” Any technique that is wrong 1/4 of the time should never, ever be used.

That is not quite what your article says (or at least it doesn’t go as far as you implied.)

This is the fifth time I’ve posted this article in response to “nuh-uh.” There won’t be a sixth. Deal with reality.

You said the labs are “only paid when there is a conviction,” which generally isn’t true. They are also paid fees in addition to court-assessed costs in most cases. I agree it is troubling, but you implied something that isn’t quite true. You should also note that I’m on your side, and dial it back a notch, bub.

Maybe if you had read the article instead of just posting it, there wouldn’t be a need for the second through fourth times. Accept reality.

I don’t know anything about forensics, but I do work in a testing lab. One of the cardinal rules is that payment for our work is never tied to whether or not the customer likes the results. To do so is to set the stage for a confict of interest.

And yes, we will happily report that your samples are cheap shit that don’t meet requirements. But probably not in those exact words :wink: