Heterodoxy, iconoclasm and spuriousness: the limits of novel expert evidence

A difficult issue arises for courts' decision-making at common law and under statutory evidentiary regimes when expert opinions are significantly unorthodox, iconoclastic or methodologically flawed. This editorial analyses the relevant evidentiary principles and the Australian jurisprudence on the subject, giving particular attention to the decisions of the South Australian Supreme Court in R v Parenzee 2007] SASC 143 and R v Parenzee 2007] SASC 316 in which expert opinions about the existence, identifiability and transmissibility of HIV and its relationship to AIDS adduced on behalf of the defence in a criminal trial were found to be seriously wanting. A variety of factors indicative of low probative value in expert opinions are distilled.