The orthodox view of shaken baby syndrome (SBS) has been predominant amongst the medical and forensic communities for decades, over which time scores of accusations of child abuse have been made based on standard diagnostic methods, which have been scientifically verified. Convictions for murder, manslaughter and child homicide have resulted in jail sentences of up to 35 years, whilst actions taken through family courts have resulted in removal of children. We discuss how belief in SBS has been systematically incorporated into Australian medical, forensic, judicial, policing, and social service institutions. We also highlight some important challenges that have been made to the orthodox views in Australia, despite the ongoing general adoption of the orthodoxy.

This chapter explains the sections of the Act and the common law principles governing the admission of opinion evidence. Critical to understanding the opinion rule is understanding what an ‘opinion’ is: this triggers the application of the rules on the exclusion or admission of such evidence.

The regulation of opinion evidence under Part 3.3 (ss 76–80) is relatively simple. Nonetheless, these rules have raised subtle problems in practice. Because of its inferential nature, opinion evidence is, in principle, excluded by s 76. However, exceptions are set out in ss 77–9.

This chapter thus explains opinion evidence, the exclusion of opinion evidence, the exceptional admission of opinion evidence and the scope of application of the opinion rule. In order to be admissible, an opinion must rationally affect, either directly or indirectly, the probability of a fact in issue in the proceedings, thus satisfying the requirements of s 55.