title: Design and results of an exploratory double blind testing program in firearms examination.
abstract: In 2010, the Netherlands Forensic Institute (NFI) and the University of Amsterdam (UvA) started a series of tests for the NFI's Firearms Section. Ten cartridge case and bullet comparison tests were submitted by various external parties as regular cases and mixed in the flow of real cases. The results of the tests were evaluated with the VU University Amsterdam (VUA). A total of twenty-nine conclusions were drawn in the ten tests. For nineteen conclusions the submitted cartridge cases or bullets were either fired from the questioned firearm or from one and the same firearm, in tests where no firearm was submitted. For ten conclusions the submitted cartridge cases or bullets were either fired from another firearm than the submitted one or from several firearms, in tests where no firearm was submitted. In none of the conclusions misleading evidence was reported, in the sense that all conclusions supported the true hypothesis. This article discusses the design considerations of the program, contains details of the tests, and describes the various ways the test results were and could be analyzed.
authors.affiliation: Netherlands Forensic Institute, Netherlands Forensic Institute, NFI, The Hague, The Netherlands. Electronic address: w.kerkhoff@nfi.minvenj.nl.
authors.forename: W
authors.initials: W
authors.lastname: Kerkhoff
authors.affiliation: Netherlands Forensic Institute, Netherlands Forensic Institute, NFI, The Hague, The Netherlands.
authors.forename: R D
authors.initials: RD
authors.lastname: Stoel
authors.affiliation: Netherlands Forensic Institute, Netherlands Forensic Institute, NFI, The Hague, The Netherlands; Leiden University, Leiden, The Netherlands.
authors.forename: C E H
authors.initials: CE
authors.lastname: Berger
authors.affiliation: Netherlands Forensic Institute, Netherlands Forensic Institute, NFI, The Hague, The Netherlands.
authors.forename: E J A T
authors.initials: EJ
authors.lastname: Mattijssen
authors.affiliation: Netherlands Forensic Institute, Netherlands Forensic Institute, NFI, The Hague, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Hermsen
authors.affiliation: VU University Amsterdam, VUA, Amsterdam, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: Smits
authors.affiliation: University of Amsterdam, UvA, Amsterdam, The Netherlands.
authors.forename: H J J
authors.initials: HJ
authors.lastname: Hardy
keywords: Blind testing; Bullet and cartridge case comparison; Fake cases; Proficiency test