FBI Notifies Crime Labs of Errors used in DNA Match Calculations Since 1999

The FBI has notified crime labs across the country that it has discovered errors in data used by forensic scientists in thousands of cases to calculate the chances that DNA found at a crime scene matches a particular person, several people familiar with the issue said.

The bureau has said it believes the errors, which extend to 1999, are unlikely to result in dramatic changes that would affect cases. It has submitted the research findings to support that conclusion for publication in the July issue of the Journal of Forensic Sciences, the officials said.

But crime labs and lawyers said they want to know more about the problem before conceding it would not make much difference in any given case.

“The public puts so much faith in DNA testing that it makes it especially important to make those the best estimates possible,” said Wright State University statistics professor Daniel R. Krane, an expert whose work has been cited by defense attorneys. “There is no excuse for a systematic error to many thousands of calculations in such a context.”...