Chaina v Presbyterian Church (NSW) Property Trust (No. 18)

In the matter of Chaina v Presbyterian Church (NSW) Property Trust (No. 18), the parties were engaged in a legal dispute concerning the admissibility of expert evidence in the context of a trial. The matter was heard in the Supreme Court of New South Wales. The central issue revolved around whether expert evidence should be excluded from consideration if some of the factual material upon which the expert relied was not present in the evidence presented during the trial, and if so, whether this should occur prior to the trial's conclusion or if the opinion itself was compromised by the excluded evidence.

The court was required to determine the principles governing the admissibility of expert evidence, particularly focusing on the extent to which an expert's report could be based on facts not in the evidence and whether this would necessitate the exclusion of the report before the trial ended. The court also needed to examine if the expert's opinion was inherently tainted by the reliance on excluded evidence, which might render the opinion unreliable.

The court held that the admissibility of expert evidence was not automatically compromised by the expert relying on facts not in the evidence, provided those facts were not central to the opinion. However, if the excluded facts materially influenced the expert's opinion, the report might be deemed unreliable and could be excluded. The court concluded that the decision to exclude the evidence should not be made until the trial's completion, allowing the court to assess the full context and significance of the excluded material. The court's reasoning was based on a careful evaluation of the expert's report and the relevance of the excluded factual material to the opinion formed. Ultimately, the court determined that the expert's opinion was not so fundamentally affected by the excluded evidence as to render it inadmissible, and thus, the report remained admissible.

The final orders of the court were that the expert evidence in question would be admitted, subject to the court's ability to revisit the issue if the excluded material's impact on the opinion became clearer as the trial progressed. The trial continued with the expert's evidence being considered alongside the other evidence presented.