Mock Jurors’ Evaluation of Firearm Examiner Testimony

dc.contributor.author Garrett, Brandon
dc.contributor.author Scurich, Nicholas
dc.contributor.author Crozier, William
dc.contributor.department Center for Statistics and Applications in Forensic Evidence
dc.date 2020-12-09T22:00:44.000
dc.date.accessioned 2021-02-25T00:41:58Z
dc.date.available 2021-02-25T00:41:58Z
dc.date.copyright Wed Jan 01 00:00:00 UTC 2020
dc.date.issued 2020-01-01
dc.description.abstract <p>Objectives: Firearms experts traditionally have testified that a weapon leaves “unique” toolmarks, so bullets or cartridge casings can be visually examined and conclusively matched to a particular firearm. Recently, due to scientific critiques, Department of Justice policy, and judges’ rulings, firearms experts have tempered their conclusions. In two experiments, we tested whether this ostensibly more cautious language has its intended effect on jurors (Experiment 1), and whether cross-examination impacts jurors’ perception of firearm testimony (Experiment 2). Hypotheses: Four hypotheses were tested. First, jurors will accord significant weight to firearm testimony that declares a “match” compared to testimony that does not (Experiments 1 and 2). Second, variations to “match” language will not affect guilty verdicts (Experiment 1). Third, only the most cautious language (“cannot exclude the gun”) would lower guilty verdicts (Experiment 1). Fourth, cross-examination will reduce guilty verdicts depending on specific language used (Experiment 2). Method: In two preregistered, high-powered experiments with 200 mock jurors per cell, participants recruited from Qualtrics Panels were presented with a criminal case containing firearms evidence, which varied the wording of the examiner’s conclusion and whether cross-examination was present. These variations include conclusion language used by practitioners, language advised by government organizations, and language required by judges in several cases. Participants gave a verdict, rated the evidence and expert in all conditions. Results: Guilty verdicts significantly increased when a match was declared compared to when a match was not declared. Variation in conclusion language did not affect guilty verdicts nor did it affect jurors’ estimates of the likelihood the defendant’s gun fired the bullet recovered at the crime scene. In contrast, however, a more cautious conclusion that an examiner “cannot exclude the defendant’s gun” did significantly reduce guilty verdicts and likelihood estimates alike. The presence of cross-examination did not affect these findings. Conclusion: Apart from the most limited language (“cannot exclude the defendant’s gun”), judicial intervention to limit firearms conclusion language is not likely to produce its intended effect. Moreover, cross-examination does not appear to affect perceptions or individual juror verdicts.</p>
dc.description.comments <p>This article is published as Garrett, B. L., Scurich, N., & Crozier, W. E. (2020). Mock jurors’ evaluation of firearm examiner testimony. <em>Law and Human Behavior, 44</em>(5), 412–423. <a href="https://psycnet.apa.org/doi/10.1037/lhb0000423" target="_blank">https://doi.org/10.1037/lhb0000423</a>. Posted with permission of CSAFE.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/csafe_pubs/73/
dc.identifier.articleid 1072
dc.identifier.contextkey 20501710
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath csafe_pubs/73
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/93882
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/csafe_pubs/73/Garrett_Scurich_Croizer_2020.pdf|||Sat Jan 15 01:46:11 UTC 2022
dc.source.uri 10.1037/lhb0000423
dc.subject.disciplines Forensic Science and Technology
dc.title Mock Jurors’ Evaluation of Firearm Examiner Testimony
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isOrgUnitOfPublication d8a3c72b-850f-40f6-87c4-8812547080c7
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