Beyond Certainty: Statistical Pitfalls in Forensic Signature Analysis
Keywords:
Forensic, United States, inconclusiveAbstract
In this commentary, we examine forensic handwriting analysis, focusing on statistical issues that arise in expert probability judgments. We highlight the challenges in accurately assessing forgery probability, especially as factors such as population size and the base rate of counterfeiting skills vary. In urban and global population contexts, even small error rates in signature matching can lead to high replication likelihood, questioning the typical high confidence expressed by forensic experts. Furthermore, we explore how base-rate assumptions shift within populations of professional counterfeiters, who significantly increase the chances of signature replication. These
findings argue for more nuanced approaches in expert testimony, emphasizing a need for improved statistical frameworks and clearer communication to ensure judicial accuracy and avoid potential misinterpretation.
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