Reason magazine's Radley Balko and Roger Koppl, director of the Institute for Forensic Science Administration at Fairleigh Dickinson University, have a new piece up at Slate on the growing reliance on forensic science and the need to fix a system that is tilted heavily in favor of prosecutors:
The use of forensic science in criminal trials is critically important. But reforms of the system are also desperately needed. It's not enough to weed out the incompetent scientists. We need to begin to monitor even the good ones. One major barrier to improving forensic evidence in criminal trials is that in most jurisdictions, the state has a monopoly on experts. Crime lab analysts and medical examiners (and to a lesser extent DNA technicians) typically work for the government and are generally seen as part of the prosecution's "team," much like the police and investigators. Yes, science is science, and it would be nice to believe that scientists will always get at the truth no matter whom they report to. But studies have consistently shown that even conscientious scientists can be affected by cognitive bias. A scientist whose job performance is evaluated by a senior official in the district attorney or state attorney general's office may feel subtle pressure to return results that produce convictions.
Some of the reforms they recommend:
Forensic counsel for the indigent. In many jurisdictions, indigent defendants aren't given access to their own forensic experts. As a result, the only expert witnesses are often testifying for the prosecution–experts that come prepackaged with the inherent biases noted above. This undermines the whole adversarial basis of our criminal justice system. Indigent defendants should be given vouchers to hire their own experts, who can review the forensic analysis and conclusions of each prosecution expert.
Expert independence. Crime labs, DNA labs, and medical examiners shouldn't serve under the same bureaucracy as district attorneys and police agencies. If these experts must work for the government, they should report to an independent state agency, if not the courts themselves. There should be a wall of separation between analysis and interpretation. Thus, an independent medical examiner would, for instance, perform and videotape the actual procedure in an autopsy. The prosecution and defense would then each bring in their own experts to interpret the results in court. When the same expert performs both the analysis and interpretation, defense experts are often at a disadvantage, having to rely on the notes and photos of the same expert whose testimony they're disputing.
Rivalrous redudancy. Whether the state uses its own labs or contracts out to private labs, evidence should periodically and systematically be sent out to yet another competing lab for verification. The state's labs should be made aware that their work will occasionally be checked but not told when. In addition to helping discover errors that might otherwise go undetected, the introduction of competition to government labs would all but remove any subconscious incentive to appease police and prosecutors and would strengthen the incentive for a more objective analysis.