Section 79 of the Evidence Act (1995) provides an exception to the opinion rule allowing forensic scientists to testify as experts if their opinion is wholly or substantially based on specialised knowledge resulting from training, study or experience. This definition has influenced the form and outcome of countless criminal and civil trials by conferring ‘expert’ status on forensic scientists and their opinions. Yet it omits a key dimension of expertise – the requirement for demonstrably superior performance by the practitioner on the relevant task. This failure to consider information about performance accuracy and the error rate of ‘experts’ – and their techniques – has led to concerns that courts and juries may misperceive or misunderstand the value and meaning of forensic science evidence. It has also resulted in critical commentary and practical guidance aimed at assisting the forensic sciences to appropriately calculate and communicate performance accuracy and error information.
This presentation outlines the status of cognitive science research and critical discourse in relation to the definition of, requirements for, and mechanisms underpinning expertise. It will also explore naïve (lay) perceptions of the reliability of forensic science evidence, their ability to identify expertise, and their understanding of expert opinions. Ultimately, this review will highlight weaknesses and challenges associated with the admission and communication of forensic science evidence that need to be addressed.