Forensic labs and experts considering blind testing to remove potential context bias
At the NIST “Error Management” Conference earlier this month, experts agreed that “a key problem…is that people who evaluate evidence from crime scenes have access to information about a case that could bias their analysis.” Unlike scientific rules and procedures on handling evidence, there are few safeguards to combat subconscious bias examiners may have. For educational purposes: Science-2015- Kelly Servick
“Replication provides the best protection against scientific fraud” (The Patriot Post)
After an uptick in fraudulent scientific publications, Gary Welton of the Patriot Post writes: “Scientific findings that are reported by only one researcher or one laboratory should be considered to be only working hypotheses. Our confidence level should increase only when findings are replicated by others.”
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While the problem of cognitive bias is important, and not that difficult to solve, one interesting aspect of forensic science that gets less attention is trying too hard. Alastair Ross, Director of the National Institute of Forensic Science, Australia New Zealand Policing, spoke at the NIST conference, and pointed out “trying too hard,” as a frequent cause of error.
Trying too hard means attempting to narrow a class of individuals beyond what the science will allow, or attempting to detect ever smaller quantities of substances, which has led to such problems as the misinterpretation of DNA evidence in mixtures. My favorite chemistry professor had a saying in his laboratory: “Think about what you are doing.” Criminalists need to keep this in mind in all aspects of their work. Do we really think that lowering the detection limit for any test by another order of magnitude will actually help the police or the jury to understand the evidence any better? How much additional error will such a process introduce?