Biasability and reliability of expert forensic document examiners

The performance of experts can be characterized in terms of biasability and reliability of their judgments. The current research is the first to explore the judgments of practicing forensic document experts, professionals who examine and compare disputed handwritten evidence to handwriting exemplars of individuals involved in criminal or civil litigation. Forensic handwriting experts determine if questioned and known handwritten items are of common authorship or written by different individuals, and present their findings in legal proceedings. The expert participants in our study (N = 25) were not aware that they were part of a research study. Thirteen participants were led to believe that they were working on a case commissioned from the prosecution and the other twelve that it was for the defense. We did not find evidence in this study that this information biased their judgments, which may make sense since document examiners (in contrast to many other forensic domains) do not primarily work within an organizational forensic laboratory culture. The lack of bias in our findings may have been also due to the stimuli we used or/and the great variability in the judgments within each group, reflecting a lack of consistency in conclusions among examiners. A detailed discussion of our findings is presented along with the limitations that may have affected our results. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study explored the judgments of practicing forensic document experts and found that their judgments were not biased by the nature of the case, possibly due to the fact that document examiners do not primarily work within an organizational forensic laboratory culture, leading to a lack of consistency.