Extra requirements for expert witnesses

Updates to the Code of Conduct for expert witnesses

On 1 January 2023 the Environment Court Practice Note 2023 came into effect, replacing the previous 2014 Practice Note.  Among other changes, the 2023 Practice Note contains important updates to the Code of Conduct for expert witnesses giving evidence in the Environment Court.

In particular, experts should take note of the additional obligations contained in section 9.3 which focuses on the requirements for expert evidence.

Among other things, section 9.3 requires an expert witness to identify any knowledge gaps they are aware of, and any uncertainties in scientific information and analyses that they rely on, and discuss the potential implications of these uncertainties and knowledge gaps in their evidence.  Expert witnesses must also provide an assessment of the level of confidence, and the likelihood of any outcomes specified, in their conclusions.

These additional requirements appear to be aimed at bolstering the helpfulness of expert evidence, and ensuring that the Court is informed of any knowledge gaps or uncertainties that may assist in deciding the weight (or relative weight) it should give to expert evidence.  Since knowledge gaps and uncertainties are often matters that witnesses are questioned or cross-examined on, these changes may also result in efficiencies by requiring experts to address these issues at the outset.

The evidence of any expert witness who has not read or does not agree to comply with the Code of Conduct may only be given with leave of the Court, so it is important that all expert witnesses are aware of and familiar with the requirements of the new Practice Note, and that expert evidence submitted to the Court contains reference to, and confirms compliance with, the new Code.

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