How a Dubious Forensic Science Spread Like a Virus
Knowledge Questions: What separates science from pseudoscience? What are the characteristics of “good” science? To what extent can we expect scientific knowledge to be “certain”?
From his basement in upstate New York, Herbert MacDonell launched modern bloodstain-pattern analysis, persuading judge after judge of its reliability. Then he trained hundreds of others. But what if they’re getting it wrong?
Although the reliability of blood-spatter analysis was never proven or quantified, its steady admission by courts rarely wavered, even as the technique, along with other forensic sciences, began facing increasing scrutiny.
In 2009, a watershed report commissioned by the National Academy of Sciences cast doubt on the whole discipline, finding that “the uncertainties associated with bloodstain pattern analysis are enormous,” and that experts’ opinions were generally “more subjective than scientific.”
Still, judges continued allowing spatter experts to testify.
A second article from Propublica
The FBI Says Its Photo Analysis Is Scientific Evidence. Scientists Disagree.
ProPublica asked leading statisticians and forensic science experts to review methods image examiners have detailed in court transcripts, published articles and presentations. The experts identified numerous instances of examiners overstating the techniques’ scientific precision and said some of their assertions defy logic.