Expert Evidence and the Problem of Privilege

Abstract

The giving of admissible evidence of opinion by experts and the concept of ‘litigation privilege’ each occupies an anomalous position within our legal system. Expert evidence is evidence provided to a court to assist in the determination of questions of science or professional skill. It is an exception to the rule that prohibits the adducing of opinion evidence and, in the case of the party-engaged expert, requires that the expert owe a paramount duty to the court. Litigation privilege is a species of legal professional privilege and a principle of public policy that operates to restrict the obligation of a party to disclose documents evidencing certain protected communications ¬in response to applications for disclosure. It is an exception to the principle that evidence that is relevant to a fact in issue is admissible. But should, for example, communications between a solicitor and an expert also be subject to litigation privilege in light of the expert’s paramount duty to the court? The issue raises questions about the role of the expert as an independent authority upon whom the courts can rely in circumstances in which a party is deploying that expert to adduce evidence in an adversarial context. The current orthodoxy, by largely maintaining the cloak of legal professional privilege in relation to draft reports and communications with experts, does little to alleviate the inherent tension between these principles. This thesis seeks to explore these issues. It also considers reforms that may ameliorate the problems that the current orthodoxy has engendered within the federal and New South Wales civil jurisdictions with respect to the party-engaged expert and the application of legal professional privilege.