Conference Proceedings and Presentations

In the wake of the 2009 NRC and 2016 PCAST Reports, the Firearms and Toolmark (FATM) discipline has come under increasing scrutiny. Validation studies like AMES I, Keisler, AMES II, Best & Gardner, and Guyll have provided important information about the validity (i.e., accuracy and reliability) of FATM examinations. However, judicial rulings like Tibbs, Ross, Shipp, Winfield, and Abruquah might not be aberrations; these cases could be the tip of the iceberg. In the past few years, I have had the opportunity to participate in judicial hearings with and against several thought leaders in the FATM community. I’m struck by three thoughts. First, each one did a very nice job. They were ethical, consistent, clear, and professional. Second, I believe we agree in many more areas than we disagree. Third, I do not believe that FATM examinations are junk science. However, there are legitimate concerns about the quantity and quality of the current validation studies. Treatment of inconclusive responses, a lack of understanding about how much of a questioned sample is needed to reach an accurate result, and treatment of missing data (e.g., participant dropout), all need to be addressed.

This talk will focus on strategies to silence the defense expert by taking the words out of their mouths. We will explore the current strengths and weaknesses of points that are raised in admissibility hearings. Hopefully, we will answer four questions: 1) What should the FATM expert say first, 2) What should the FATM expert avoid saying, 3) How do we keep from skating onto thin ice with our expert testimony, and 4) What are the strongest arguments in favor of FATM admissibility. Finally, we will review resources for FATM examiners and forensic science service providers to deepen their knowledge of mathematics, statistics, probability and physical science.