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Corzo R, Hoffman T, Ernst T, Trejos T, Berman T, Coulson S, Weis P, Stryjnik A, Dorn H, Pollock EC, Workman MS, Jones P, Nytes B, Scholz T, Xie H, Igowsky K, Nelson R, Gates K, Gonzalez J, Voss LM, Almirall J. An interlaboratory study evaluating the interpretation of forensic glass evidence using refractive index measurements and elemental composition. Forensic Chem 2021; 22. [PMID: 34485765 DOI: 10.1016/j.forc.2021.100307] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Seventeen laboratories participated in three interlaboratory exercises to assess the performance of refractive index, micro X-ray Fluorescence Spectroscopy (μXRF), and Laser Induced Breakdown Spectroscopy (LIBS) data for the forensic comparison of glass samples. Glass fragments from automotive windshields were distributed to the participating labs as blind samples and participants were asked to compare the glass samples (known vs. questioned) and report their findings as they would in casework. For samples that originated from the same source, the overall correct association rate was greater than 92% for each of the three techniques (refractive index, μXRF, and LIBS). For samples that originated from different vehicles, an overall correct exclusion rate of 82%, 96%, and 87% was observed for refractive index, μXRF, and LIBS, respectively. Special attention was given to the reporting language used by practitioners as well as the use of verbal scales and/or databases to assign a significance to the evidence. Wide variations in the reported conclusions exist between different laboratories, demonstrating a need for the standardization of the reporting language used by practitioners. Moreover, few labs used a verbal scale and/or a database to provide a weight to the evidence. It is recommended that forensic practitioners strive to incorporate the use of a verbal scale and/or a background database, if available, to provide a measure of significance to glass forensic evidence (i.e., the strength of an association or exclusion).
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Affiliation(s)
- Ruthmara Corzo
- Florida International University, Miami, FL, United States.,National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Tricia Hoffman
- Florida International University, Miami, FL, United States
| | - Troy Ernst
- Michigan State Police, Grand Rapids Forensic Laboratory, Grand Rapids, MI, United States
| | | | - Ted Berman
- Florida Department of Law Enforcement, Orlando, FL, United States
| | - Sally Coulson
- Institute of Environmental Science and Research, Auckland, New Zealand
| | - Peter Weis
- Bundeskriminalamt, KT 42, Wiesbaden, Germany
| | | | | | - Edward Chip Pollock
- Sacramento County DA's Office, Laboratory of Forensic Services, Sacramento, CA, United States
| | | | - Patrick Jones
- Kansas City Police Crime Laboratory, Kansas City, MO, United States
| | | | | | | | - Katherine Igowsky
- Minnesota Bureau of Criminal Apprehension, St. Paul, MN, United States
| | - Randall Nelson
- Tennessee Bureau of Investigation, Nashville, TN, United States
| | - Kris Gates
- Oregon State Police Forensic Laboratory, Clackamas, OR, United States
| | - Jhanis Gonzalez
- Applied Spectra Incorporated, West Sacramento, CA, United States
| | | | - Jose Almirall
- Florida International University, Miami, FL, United States
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