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Evaluation of Match Criteria Used for the Comparison of Refractive Index of Glass Fragments
Article first published online: 6 JAN 2011
2011 American Academy of Forensic Sciences. Published 2011. This article is a U.S. Government work and is in the public domain in the U.S.A.
Journal of Forensic Sciences
Volume 56, Issue 2, pages 491–500, March 2011
How to Cite
Garvin, E. J. and Koons, R. D. (2011), Evaluation of Match Criteria Used for the Comparison of Refractive Index of Glass Fragments. Journal of Forensic Sciences, 56: 491–500. doi: 10.1111/j.1556-4029.2010.01634.x
Presented at the 61st Annual Meeting of the American Academy of Forensic Sciences, February 20, 2009, in Denver, CO.
The Visiting Scientist Program is an educational opportunity funded by the FBI Laboratory and administered by the Oak Ridge Institute for Science and Education.
Publication No. 09-07 of the Laboratory Division of the Federal Bureau of Investigation (FBI). Mention of trade names is for information purposes only and does not imply endorsement by the FBI or the federal government.
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- Issue published online: 22 FEB 2011
- Article first published online: 6 JAN 2011
- Received 27 Mar. 2009; and in revised form 2 Oct. 2009; accepted 10 Oct. 2009.
- forensic science;
- trace evidence;
- refractive index;
- statistical methodology
Abstract: For comparative glass examinations, the refractive indices (RIs) of recovered glass fragments are often compared to a test interval defined by measurements from a broken glass object. RI measurements from five modern float glasses were used via resampling to assess the frequencies of false exclusion errors for eight test criteria as functions of the number of measurements. The test criteria were based on ranges, fixed intervals, and multiples of standard deviations of the known source measurements. The observed error rates for the eight tests studied are between zero and c. 35%, depending upon the match criteria, the number of measurements, and the RI distribution for a glass source. The results of this study can be used to predict the false exclusion rate for a test criterion under a given set of conditions or to select test criteria that result in a desired error rate for these typical sheet glasses.