The short answer to this question is ‘yes’, bias is a concern. However, that is far too simplistic a response.

The bottom line is that every examiner must be aware of the potential for bias in their work, the various ways in which it may manifest, and what can and should be done to minimize such concerns. At an absolute minimum, examiners must be able to explain any steps they have taken to achieve that goal so that the trier can be assess the effectiveness of any such steps. The steps taken will undoubtedly differ for a private examiner working alone, versus a larger laboratory with considerably more resources and mechanisms they might employ.

In general, ‘bias’ is a potential concern for any and every human endeavour that involves or requires evaluation and reasoning. Since every forensic evaluation is a human-based activity involving mainly subjective assessment (even in those situations where there might be an empirical basis to support that assessment), it follows that the potential for bias will be present. It also follows that every examiner needs to be aware of this prospect when doing their work.

On the positive side of things, examiners that follow published guidelines and best practice documents will be utilizing procedures that are designed to help minimize this type of concern. For example, examiners applying the logical approach to evidence evaluation must expressly consider (and disclose) relevant framework information, as well as all relevant propositions considered in the course of their evaluation. Doing so reduces the potential for bias in the evaluation process.