Expert Evidence in Criminal Trials

Background

In every trial, juries are required to make determinations of disputed factual issues. Where to do so requires specialised knowledge, experts in the relevant field are called upon to help the jury interpret the evidence. This is to ensure that jurors do not draw mistaken inferences from the evidence. Although juries should not defer to experts' knowledge and opinions, there remains the danger that they will do so, especially if the field of expertise is particularly difficult to comprehend.

This gives rise to a real danger if there are legitimate questions about the validity of the expert's opinion. This may be because the expert's field is a new or developing science with little in the way of peer review, or because there are doubts as to the validity of the methodology employed. The problem is accentuated if there is no available expert in the same field who can be called by the opposing party to provide an effective criticism. In such cases, the jury may have no option but to defer to the view of the expert.

A related problem is that judges, advocates and jurors may not appreciate the limitations of expert – and particularly scientific – evidence.

A number of cases in recent years have suggested that these are real difficulties which require a solution. In this project we are seeking to address the problems outlined above associated with the admissibility and understanding of expert evidence in criminal proceedings.

We intend to publish a consultation paper on the admissibility of expert evidence in late 2008.

For more information, contact the criminal law team or go to the team page.

NOTE - We are happy to provide information about our projects. However, we cannot give legal advice or deal with individual cases. Nor do we help with student assignments.