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Contextual Bias: What Bloodstain Pattern Analysts Need to Know

Abstract

Bloodstain Pattern Analysis (BPA) is a highly involved process. In addition to the complexities and ambiguities of the patterns themselves, examiners are often presented with considerable information about other aspects of the investigation. There is growing concern that this information could unduly influence both pattern classification and scene reconstruction, in a process known as contextual bias. In this article, we introduce the notion of contextual bias, and look at its potential impact on forensic scientists’ decisions and, more specifically, the potential for bias in BPA. Based on the picture so far, we suggest ways to mitigate bias in BPA, and discuss future directions for research in this field. To conclude, we discuss the implications of contextual bias as an expert witness in the courtroom.

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