Judge Kozinski on scientific evidence

Ninth Circuit Court of Appeals Judge Alex Kozinski — has recently published an article in the Georgetown Law Journal providing 12 reasons we should worry about the criminal justice system. His former law clerk and blogger Eugene Volokh has serialized the article for theWashington Post. This is the third in a series of Judge Kozinski's concerns with the criminal justice system, through the analysis of Mr. Volokh.

With the exception of DNA evidence forensic evidence has some serious shortcomings: “Spectrographic voice identification error rates are as high as 63%, depending on the type of voice sample tested. Handwriting error rates average around 40% and sometimes approach 100%. False-positive error rates for bite marks run as high as 64%. Those for microscopic hair comparisons are about 12% (using results of mitochondrial DNA testing as the criterion).”
Other fields of forensic expertise, long accepted by the courts as largely infallible, such as bloodstain pattern identification, foot and tire print identification and ballistics have been the subject of considerable doubt. Judge Nancy Gertner, for example, has expressed skepticism about admitting expert testimony on handwriting, canines, ballistics and arson. She has lamented that while “the Daubert-Kumho standard [for admitting expert witness testimony] does not require the illusory perfection of a television show (CSI, this wasn’t), when liberty hangs in the balance — and, in the case of the defendants facing the death penalty, life itself — the standards should be higher . . . than [those that] have been imposed across the country.”
Some fields of forensic expertise are built on nothing but guesswork and false common sense. Many defendants have been convicted and spent countless years in prison based on evidence by arson experts who were later shown to be little better than witch doctors. Cameron Todd Willingham may have lost his life over it.

Read my columns on bite-mark identification, hair analysis and eyewitness identification.