Forensic science testing: The forensic filler-control method for controlling contextual bias, estimating error rates, and calibrating analysts’ reports

A large share of forensic science techniques involving the analyis of physical evidence have never been validated scientifically. The ational Academy of Sciences (NAS, 2009) concluded that, with the xception of nuclear DNA analysis, no forensic method has been rigrously shown to consistently and with a high degree of certainty emonstrate a connection between evidence and a specific indiidual or source and have not developed evidence-based estimates f error rates. The NAS report also noted that forensic analysts1 are ubject to “contextual bias,” which occurs when the analyst is influnced by knowledge about the suspect’s background or other case nformation. Kassin, Dror, and Kukucka (2013) reviewed basic social and cogitive psychology supporting the concern regarding contextual bias nd makes a compelling case for the value of psychological science o demonstrate and understand contextual bias in forensic testing. nfortunately, even if contextual bias were neutralized, it leaves ntouched significant problems identified by the NAS report: Is he technique reliable? What is the error rate? Is the analyst cometent to conduct the procedure? Are analysts overstating their onclusions? Forensic science testing and testimony has proliferted without answers to these questions. In effect, a large share f “forensic science” techniques, almost all of which were develped by people in law enforcement rather than scientists, end up oming down to what we call the “inter-ocular” test in which the