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The Basics of Error Rates in Pattern Evidence
50 Minutes
Originally presented at the 2015 Impression, Pattern and Trace Evidence Symposium.

One of the Daubert prongs of admissibility for scientific expert testimony is the known or potential error rate of a technique. Thus, examiners are often asked about the discipline error rate on the stand. Numerous error rate studies have been undertaken in an attempt to provide this number. But just what is really sought? What are the different types of error rates? How are they calculated and what do they mean? This lecture will describe some commonly reported error rates for pattern evidence, and will demonstrate how to calculate them.

After attending this presentation, attendees will understand the most commonly calculated error rates and will be able to calculate them themselves. They will also be able to read error rate studies in the literature and have a better understanding of what is being reported, and how it should be appropriately used in the courtroom.

This webinar was recorded in its entirety at the time of the live event in order to capture the one on one interaction with the presenter.


Heidi Eldridge
Research Forensic Scientist, RTI International.

This event is funded through a Cooperative Agreement (2011-DN-BX-K564) from the National Institute

of Justice (NIJ), Office of Justice Programs (OJP), and U.S. Department of Justice (USDOJ). The views,

policies, and opinions expressed are those of the authors and contributors and do not necessarily reflect

those of the NIJ, OJP, or USDOJ.