ABSTRACT
This chapter presents information, both theoretical and practical, about the logical approach to evidence evaluation, primarily in reference to forensic document examination. The role of any expert witness is to provide the court, and more specifically the trier, with a proper understanding of evidence that falls within that examiner’s scope of expertise. When applying the logical approach, an examiner must focus on the probability of the findings, given the competing propositions. Examiners are subject-matter experts with the knowledge, skill, and ability to assess what particular findings mean in a given context or scenario. Numeric probabilities assigned by an examiner and informed in some appropriate manner that the examiner can disclose and discuss should be the underlying basis for that examiner’s opinion. The knowledge examiners draw upon in a forensic context to assign probabilities is based on different, yet compatible, types of information.
