Snapshot
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Recent High Court decisions have provided some clarity on the developing law on the admissibility of expert evidence.
- For expert opinions to be admissible, they need to identify assumptions, underlying bases and the specialised knowledge on which they are said to be based.
- This article is the first of two parts and will review the context and ongoing significance of transparency for the admissibility of expert evidence, as developed in Lang v The Queen.
The admissibility and weight of expert evidence hinge on transparency—both in the assumptions made and the reasoning employed. This article explores how courts have grappled with this issue, culminating in the High Court’s decision in Lang v The Queen [2023] HCA 29 (‘Lang’). The judgment underscores that expert opinions must be more than authoritative assertions; they must be grounded in specialised knowledge and clearly reasoned from identifiable facts. This article unpacks the evolution of these evidentiary principles and their practical implications for legal practitioners.
In part two, BQ v The King [2024] HCA 20 will be discussed: a decision that further refines the boundaries of admissibility and explores how courts assess the reliability and relevance of expert psychiatric evidence in criminal trials.
