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Lessons Learned from Proficiency Test Results in Bloodstain Pattern Analysis

Event Dates
Event Duration
1 hour

The Daubert ruling by the Supreme Court established “the known or potential rate of error” as one of several factors to be used when assessing the scientific reliability or validity of proffered expert witness’s opinion.  Since the Daubert ruling in 1993, research has been performed in all disciplines in forensic science, including bloodstain pattern analysis (BPA), to provide insight into the rate of error for various conclusions.

Only a limited number of studies have been published to date on the reliability of BPA conclusions; however, there are other means of evaluating erroneous conclusions. Studying the responses to proficiency tests and comparing these responses to the ground truth is one such method.  While there are several limitations to using proficiency tests to examine erroneous conclusions for any discipline in forensic science, there is still value in this type of investigation.

This presentation will review lessons learned from a detailed examination of over fifteen years of proficiency tests with a specific emphasis on pattern classification conclusions.  A number of questions will be addressed, including: Can any insight be provided regarding the overall rate of error for pattern classification in BPA?  Are certain broad or specific pattern types more prone to erroneous conclusions than others?  Is there any way to connect the rate of erroneous conclusions with the training and education of participants?  Can the submitted responses, specifically the incorrect responses, be used to provide guidance for how the discipline moves forward with pattern classification?  This presentation will discuss these questions and more.

Date Created: November 19, 2020