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Scientific Working Group on Bloodstain Pattern Analysis: Topics to Consider in Preparation for an Admissibility Hearing on Bloodstain Pattern Analysis

NCJ Number
Date Published
January 2008
10 pages
This paper provides guidance on how to prepare for an admissibility hearing that addresses bloodstain pattern analysis (BPA).
In most settings, an admissibility hearing is for the purpose of testing the general acceptance of a scientific technique and/or discipline through the testimony of experts, rather than to advance the evidence yielded by the technique or dispute its role in the case-in-chief. In addition to reviewing the testimony presented at an admissibility hearing, the court may also consider and/or require the submission of materials such as scientific literature, transcripts of previous BPA testimony, previous appellate and/or trial court decisions, and/or the qualifications of any expert who may provide testimony at any subsequent admissibility hearing. A BPA expert should be prepared to provide documentation of his/her training and experience. He/she should also consider using visual aids in order to demonstrate major points that support the scientific validity and methodology of BPA. After reviewing admissibility standards for scientific evidence under the U.S. Supreme Court decisions in "Daubert" (1993) and the earlier decision in Frye (1923), the paper poses and answers questions likely to be central in a BPA admissibility hearing. The questions and issues discussed are the nature and characteristics of BPA, the purpose of BPA, the principles of BPA, the methodology used when conducting BPA, the scientific principles and methods of BPA that are used in other fields, the general acceptance of BPA methods in the scientific community, the use of BPA in the forensic science community throughout the world, published studies on the reliability and validity of BPA, error rate associated with BPA methodology, and administrative controls for ensuring that BPA results are reliable. Guidance is also provided on the preparation of testimony. 2 notes