The writer is a professor of criminology and law at the University of California at Irvine, a member of the Human Factors Subcommittee of the National Commission on Forensic Science and vice chair of the Human Factors Committee of the Organization of Scientific Area Committees, a federal body charged with promulgating standards and guidelines on forensic science.
The top managers of the District’s highly regarded crime laboratory were forced to resign or terminated last month after a dispute between the crime lab and the U.S. Attorney’s Office over interpretation and reporting of DNA evidence. News reports suggested it was simply a matter of incompetence.
Outside experts hired by the U.S. Attorney’s Office issued a highly critical report. Their criticisms were supported by an audit performed on behalf of the mayor’s office by a national accrediting agency. The mayor and other city officials undoubtedly assumed that, if the lab could not figure out the right way to do DNA testing, the managers should be replaced. But that simple-minded analysis reflects a serious misunderstanding about the details of the matter and the larger issues at stake.
A key issue is whether the crime laboratory will remain independent from law enforcement. In 2009, the National Academy of Sciences recommended that crime labs be separated from law enforcement control. The academy concluded that many of the problems that plague forensic science — inadequately validated methods, bias, overstatement of findings — are partly attributable to excessive influence by police and prosecutors, who rely heavily on forensic science evidence to obtain convictions.
The District followed the academy’s recommendation. In 2011, the D.C. Council established the Department of Forensic Sciences as an independent agency. Max M. Houck, a highly regarded forensic scientist, was appointed director. The laboratory began operation in October 2012 and quickly obtained accreditation, drawing nationwide attention from those interested in reform and improvement of forensic science.
Houck worked to ensure the independence and transparency of the laboratory. With the help of the lab’s legal counsel, he developed new lines of communication between the laboratory and the groups it served — including police, prosecutors and defense lawyers. The laboratory ended a policy that had allowed prosecutors to have preferential access to laboratory information and to control what defense lawyers were allowed to see. Under the new administration, prosecutors and defense lawyers were given equal access.
That the lab’s legal counsel was among those sacked suggests that the firings were about more than interpretation of DNA tests. If misinterpretation is the real problem, why was firing the laboratory’s legal counsel the solution? Were the complaints about DNA interpretation an excuse to strike back at a laboratory management that had denied them some of the prerogatives that laboratories have traditionally granted to prosecutors — a way to bring an independent laboratory back under law enforcement control?
The complaints concerned the lab’s interpretation of DNA tests in a special class of cases that are notoriously difficult to interpret — those in which the quantity of DNA recovered is too small to yield a complete genetic profile. To draw conclusions from such evidence, analysts must make subjective judgments about matters that cannot be determined with certainty, such as the exact number of contributors and the probability that the test failed to detect certain genetic characteristics of certain contributors.
Reasonable experts have long been divided over the best way to analyze such evidence and how to report the results. While the method used by the D.C. lab is open to criticism, a 2013 study by the National Institute of Standards and Technology suggests that a majority of DNA laboratories in the United States follow the same method. The audit team pointed to several cases in which it deemed the lab’s interpretations to be problematic, but one could find similar examples in the casework of accredited crime laboratories nationwide.
These problems have never caused an accrediting agency to demand suspension of testing in a DNA laboratory. Why was that step taken now?
It is noteworthy that the audit agency met privately with representatives of the U.S. Attorney’s Office and experts they hired before the audit. A request by the Public Defender Service to have a representative at the meeting was denied.
Observers will be watching very closely to see whether the new management of the laboratory maintains the policies of openness and independence ushered in by Houck, or whether the laboratory returns to a more traditional model in which prosecutors have preferential access and influence.
In any event, this sends a strong message to laboratory directors nationwide who come into conflict with local prosecutors. The message is be afraid, be very afraid. That, in itself, is a serious setback for efforts to protect the scientific independence of crime laboratories.
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