Wednesday, April 18, 2012

'The Real CSI'

PBS Frontline last night broadcast a nearly hour-long feature story titled "The Real CSI," focusing on forensic errors caused by "cognitive bias" that can lead to mistakes like those made by fingerprint examiners in the infamous Brandon Mayfield case. Here's the video:

Watch The Real CSI on PBS. See more from FRONTLINE.

The first part of the story focuses on the surprising subjectivity of fingerprint examination, honing in on false accusations of terrorism against Oregon attorney Brandon Mayfield. Then they move on to the high rate of false positive errors in bite mark evidence, address the relative lack of meaningful credentialing in many forensic disciplines, and the inability of courts to weed out poorly functioning experts. It was fascinating to hear a latent fingerprint examiner with 40 years experience saying that moment one decides that two prints match amounts to a "leap of faith."

One interesting segment of the show discussed the infamous Casey Anthony prosecution out of Florida to show how high-profile cases can pressure prosecutors to employ questionable forensic evidence - in particular the so-called "smell of death" testimony. The jury in that case heard 37 experts from a dozen different forensic disciplines. The case was unusual in that respect, said her attorney, because the defendant was able to pay for a robust defense thanks to money paid her by ABC News for access to family photos. For those whose cases haven't become national entertainment fodder and can't get a news network to pay for defense experts, I suppose they're out of luck.

RELATED (4/20): Check out this story out of the UK about a police officer falsely accused of perjury based on a fingerprint mismatch.

See related Grits posts:


jimbino said...

I think that "honing in" should read "homing in." Common confusion.

Gritsforbreakfast said...

I've heard that critique before jimbino, but IMO 'hone' as in to sharpen or refine a point, also works. The phrases arose at roughly the same time, and according to this source, "there is quite a bit of semantic support for the hone in on variant. There's so much semantic support in this case that hone in on is by no means implausible as a coinage on its own. Google suggests that the two variants are about equally common today, and the hone in on variant now occurs in places like MIT press releases and Washington Post presentations of Reuters newswire stories."

Thanks for pointing it out, though. You made me go look it up and there's little I enjoy more than a good etymology excursion. :)

Arachne646 said...

The D.A. in the documentary was so sure that forensic evidence and testimony was nearly always right because there had only been a few cases where glaring errors had been discovered. I'm sure this illogical way of thinking is exactly the roadblock to the goal of getting science incorporated into forensic testimony.

One lawyer said that lawyers, judges, and juries are scientifically illiterate (he didn't say stupid), so guidelines need to be in place so that junk science like polygraphs are not admissible in court. Courts are not competent to decide what is scientifically validated and what is not.