More DNA

This has been a good week for DNA news. Unfortunately, it's not all been good news. Today's Times picks up and builds on the story I linked a couple of days ago about the too-often forgotten human element of DNA evidence.

DNA testing, when properly conducted and interpreted, can provide categorical proof of guilt or innocence. Its role in the exoneration of more than 120 people has captured the public imagination. But this uniquely authoritative tool can also play a role in wrongful convictions.

"It is powerful evidence both to convict and to exonerate," said Peter Neufeld, a founder of the Innocence Project at Cardozo Law School, a program that works to free innocent people in prison. "It's kind of a truth machine. But any machine when it gets in the hands of human beings can be manipulated or abused."

[. . .]

Elizabeth A. Johnson, an expert in DNA testing in California, said everyone in the criminal justice system should be wary of accepting reports concerning DNA evidence without testing their conclusions.

"It is very, very reliable if you do two things right: if you test it right, and if you interpret the results right," Ms. Johnson said. "The problem is that jurors think it's absolute and infallible."

The problem with DNA testing is not that it results in falsely positive results. The problem is the human factor.

"So many of the people who give DNA testimony," said Stephen B. Bright, the director of the Southern Center for Human Rights, "went to two weeks of training by the F.B.I. in Quantico, say, and they are miraculously transformed from beat policemen into forensic scientists."

And so the white porn-laden van drives on.