When determining probative value for the purposes of balancing the probative value of evidence against the danger of unfair prejudice to the accused, the High Court has favoured an approach that appears incompatible with a rational response to the treatment of opinions based on specialised knowledge. A majority in IMM v The Queen concluded that when determining the probative value of evidence for the purpose of s 137 the trial judge should take the contested evidence at its highest. In doing so the trial judge is prevented from considering the reliability of the evidence or the credibility of the witness. This article explains why, whatever the merits of such an approach might be in relation to other types of evidence and witness, trial judges are incapable of assessing the probative value of most forms of scientific, medical and technical opinion evidence-particularly forensic science and forensic medicine evidence-without insight into reliability or trustworthiness demonstrated through formal evaluation. Using examples, the article explains why blinding trial judges to reliability and validity obliges them to speculate about the value of procedures and opinions. Not only are trial judges obliged to speculate, but inattention to the results of formal evaluation has detrimental system effects, elides a range of serious dangers to the accused and denudes s 137 of value as a trial safeguard.
|Number of pages||49|
|Journal||Melbourne University Law Review|
|Publication status||Published - 1 Feb 2017|