Last night, PBS broadcast “Forensics on Trial” on Nova, the network’s terrific science show.  My take: the show got most of the issues regarding forensic science right, but not all.  And I think it might leave a misleading impression on some viewers.

Here’s a quick list of some of the things the program got right:

* The Brandon Mayfield fingerprint fiasco set in motion deep scrutiny of forensic science, culminating in the National Academy of Science 2009 report, “Strengthening Forensic Science in the United States.”

* According to that report, aside from DNA, most forensic science isn’t science at all but a craft based on human interpretation, subject to all of the cognitive flaws one would expect.

* Most of forensic science operates without standards, accountability, or basic certification.

But I had some reservations:

* The show conveyed a sense that the lack of scientific rigor in forensic methods would be solved by shiny new high-tech gadgetry.  Too little attention was paid to the ways we should address more basic flaws: the lack of real data on which to base our judgments about the sources of the evidence we find; the absence of standard laboratory practices, such as blind testing,  to protect against cognitive biases and flaws.

* The show failed to probe into the weaknesses of some of the lamest forensic disciplines, such as tire and shoe prints, hair and fiber matching, and the like.  Some of this was mentioned, but only in passing.

* The segment on bite mark identification was particularly striking.  It did a good job of exposing how this “discipline” put an innocent man in jail for fifteen years.  But it made it seem as if the problem was shoddy use of a legitimate method, when the issue is more fundamental: bite marks on skin are not consistent, and they change as the body tissue changes, moves, etc.

* I recall nothing about fraudulent forensics — so-called “dry labbing” that is now rocking the Jamaica Plain lab in Massachusetts, and that has shown up again and again in other places.  (Paging Fred Zain…paging Joyce Gilchrist…)

A worthy effort?  Yes, no question.  But I was hoping for better.

Reaction, readers?

  1. FleaStiff says:

    I had expected greater emphasis on procedural issues such as contamination during receipt of evidence, bias introduced by police disclosures to crime lab personnel, politically motivated perjury such as in the Police Constable McKee case.

    I also expected a more intense scrutiny of terms such as “match” and “consistent with” since these troublesome terms are rarely understood by jurors.

  2. James Dowling says:

    Hi David: I could not agree with you more! What the piece failed to adequately address is the fact that as long as we have “human beings” interpreting the “science”, we are always going to have flaws and possible imperfect interpretations of the science. I have always been of the mindset that all evidence should be double & triple checked and corroborated from several different sources. For now, DNA seems to hold out the most hope for somewhat accurately assessing our evidence going into the future. By and large, clear, high-resolution, digital video (that has proven to be unaltered) seems to be the best evidence to identify a perpetrator. Of course, that happens very rarely. So, we are left with the foibles of humans interpreting so-called “science.”

    James Dowling
    Retired law enforcement
    Criminal Justice instructor

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