Judge Kozinski: DNA is not infallible

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 the Washington Post.

This is the fourth in a series of Judge Kozinski's concerns with the criminal justice system, through the analysis of Mr. Volokh.

DNA evidence is infallible. This is true to a point. DNA comparison, when properly conducted by an honest, trained professional will invariably reach the correct result. But the integrity of the result depends on a variety of factors that are, unfortunately, not nearly so foolproof: the evidence must be gathered and preserved so as to avoid contamination; the testing itself must be conducted so that the two samples being compared do not contaminate each other; the examiner must be competent and honest.

As numerous scandals involving DNA testing labs have shown, these conditions cannot be taken for granted, and DNA evidence is only as good as the weakest link in the chain.