Lessons Learned from Proficiency Test Results in Bloodstain Pattern Analysis

Lessons Learned from Proficiency Test Results in Bloodstain Pattern Analysis

This webinar originally occurred on April 15th, 2021
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 reviewed 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 were 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 discussed these questions and more.

Detailed Learning Objectives

  1. Attendees will learn how the results of proficiency tests can be used to provide limited information on the reliability of bloodstain pattern classification.
  2. Attendees will learn potential reasons why certain patterns had higher incorrect conclusions.
  3. Attendees will learn how modifications to classification criteria and analyst training can assist in reducing erroneous bloodstain pattern classifications.


Jeremiah Morris - Forensic scientist and technical leader in Bloodstain Pattern Analysis at the Johnson County Sheriff’s Office Criminalistics Laboratory in Kansas


Funding for this Forensic Technology Center of Excellence event has been provided by the National Institute of Justice.-

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