Revisiting admissibility: A review of the challenges in judicial evaluation of expert scientific evidence
Authors Jo-Marí Visser, Ulrich Kruger
Affiliations: Senior Lecturer in Law, University of the Free State; Candidate Attorney, Law Society of the Northern Provinces
Source: South African Journal of Criminal Justice, Volume 31 Issue 1, p. 1 – 25
Research has shown that criminal courts in common law jurisdictions generally take a liberal approach to the admission of incriminating expert evidence and leave considerations of reliability and methodological validity until the evaluation stage. This article investigates the ability of presiding offcers to accurately evaluate expert evidence by describing the factors that complicate this task. These factors include: the complex and technical nature of expert evidence and the specialisation required to understand it, as well as bias at different levels of trial. The article also reviews some strategies meant to assist presiding offcers in accurately evaluating often highly technical evidence, from adversarial safeguards to the development of strict admissibility rules. The article confrms that judges in bench trials are in as poor a position as laypersons on jury panels to accurately evaluate expert evidence. For this reason, South Africa should adopt research and policy strategies to encourage a more analytical approach during the admissibility stage in criminal trials. The aim of such an approach must be to conceptualise and apply effective rules to help judges identify and exclude unreliable expert evidence, and to invite prosecutors and legal representatives to partake in the process of rooting out unreliable evidence.