By Kelly Servick
Originally published March 7, 2016
Here is an excerpt:
Testing examiner accuracy using known samples can give the judge or jury a sense of general error rates in a field, but it can’t describe the level of uncertainty around a specific piece of evidence. Right now, only DNA identification includes that measure of uncertainty. (DNA analyses are based on 13 genetic variants, or alleles, that are statistically independent, and known to vary widely among individuals.) Mixtures of genetic material from multiple people can complicate the analysis, but DNA profiling is “a relatively easy statistical problem to solve,” says Nicholas Petraco, an applied mathematician at City University of New York’s John Jay College of Criminal Justice in New York City. Pattern evidence doesn’t operate under the same rules, he says. “What’s an allele on a tool mark?”; “What’s an allele on a hair or fiber?”
The article is here.
Note: This article addresses evidence such as fingerprints, that can have error. What does this say about neurological or psychological "evidence" in terms of accuracy, validity, and reliability?