Wednesday, July 17, 2013

How accurate is forensic analysis?

This Washington Post article highlights a review of death penalty convictions "... in which FBI forensic experts may have mistakenly linked defendants to crimes with exaggerated scientific testimony ..."

Within the article, there's an interactive info-graphic on the reliability of certain "forensic analysis" domains. "Body changes registered by polygraph equipment can be subjective to interpret, caused by anxiety rather than guilt." "A 2003 National Academy of Sciences panel found polygraph testing lacks sufficient scientific validity and accuracy to justify its use in screening federal employees but useful as an investigative tool. Several federal circuit and state courts deem polygraph evidence inadmissible." In spite of this, many LE agencies continue to use the Polygraph exam to screen recruits and internal transfers to sensitive assignments. One is left to wonder how many false positives have prevented otherwise fit candidates from gaining employment in LE. I know from my own experiences with the polygraph, wondering that since the attachments don't fit on my larger than average body, and I barely fit in the special chair ... how can the results be accurate or valid, much less reliable and repeatable.

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