Novices cannot fill the examiners' shoes: Evidence of footwear examiners' expertise in shoe comparisons

R Chapman; S Summersby; T Lang; J Raymond; K Ballantyne

doi:10.1016/j.scijus.2023.07.004

Novices cannot fill the examiners' shoes: Evidence of footwear examiners' expertise in shoe comparisons

Sci Justice. 2023 Sep;63(5):598-611. doi: 10.1016/j.scijus.2023.07.004. Epub 2023 Jul 22.

Authors

R Chapman¹, S Summersby², T Lang³, J Raymond⁴, K Ballantyne⁵

Affiliations

¹ Major Crime Scene Unit, Victoria Police Forensic Services Department, 31 Forensic Drive Macleod, VIC 3085, Australia.
² Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, 31 Forensic Drive Macleod, VIC 3085, Australia. Electronic address: Stephanie.Summersby@police.vic.gov.au.
³ Major Crime Scene Unit, Victoria Police Forensic Services Department, 31 Forensic Drive Macleod, VIC 3085, Australia; Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, 31 Forensic Drive Macleod, VIC 3085, Australia.
⁴ Forensic Evidence and Technical Service Command, New South Wales Police Force, 151-241 Goulburn Street Surry Hills, NSW 2010, Australia.
⁵ Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, 31 Forensic Drive Macleod, VIC 3085, Australia.

PMID: 37718007
DOI: 10.1016/j.scijus.2023.07.004

Abstract

The value of a footwear examiner's opinion centres on their ability to determine whether a particular shoe made an impression with greater accuracy than a novice. However, there has been limited research on the expertise of footwear examiners and the accuracy and reproducibility of their decisions. In the current study, we measured the accuracy and consensus of 31 footwear examiners versus a comparison group of 29 novices. Participants completed 20 ground truth known mock shoe comparisons. Results demonstrated that footwear examiners were more accurate than novices, regardless of comparison difficulty. Overall, on trials where probative decisions were given, examiners made false identifications and false exclusions on a total of 3% and 2% of trials, while novices made false identifications and false exclusions on a total of 19% and 17% of trials. Examiners also demonstrated better consensus in their opinions than novices, although both groups demonstrated low levels of agreement in their responses and variability in their interpretation of the conclusion scale. In summary, these findings support the proposition that footwear examiners show expert-level performance in matching known and unknown footwear impressions. These performance estimates may help the criminal justice system to appropriately value footwear examination evidence.

Keywords: Accuracy; Error rates; Expertise; Footwear examiners; Forensic footwear evidence; Reproducibility.

MeSH terms

Humans
Reproducibility of Results
Shoes*