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Abstract:
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In the United States, footwear examiners make decisions about the sources of crime scene shoe impressions using subjective criteria. This has raised questions about the accuracy, repeatability, reproducibility, and scientific validity of footwear examinations. Currently, most footwear examiners follow a workflow that compares a questioned and test impression with regard to outsole design, size, wear, and randomly acquired characteristics (RACs). We strive to augment this workflow with computer algorithms and statistical analysis so as to improve in the following areas: (1) quantifying the degree of correspondence between the questioned and test impressions with respect to design, size, wear, and RACs, (2) identifying case-relevant pairs containing known mated and known non-mated impressions from a reference database, and (3) using data visualization to provide an empirical basis for interpreting comparison outputs (e.g., algorithm scores or examiner conclusions). The NIST footwear research team will summarize its progress in applying the NIST Footwear Impression Comparison System, FICS, to comparisons from a recent black box study for footwear examiners conducted by the FBI.
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