Translating Science Into Law: The Problems and Potential Prejudice of DNA Evidence and Statistical Data

Abstract

This paper examines the admissibility of different forms of DNA evidence in light of the Australian decision in R v Aytugrul. While exclusion percentages and likelihood ratios are mathematically equivalent, there is significant evidence suggesting that they are likely to be interpreted differently. The psychological and statistical research underlyling the minority ruling of McClellan CJ are considered, and found to be highly persuasive. There is no current case law in New Zealand on the topic, so the issue is considered in light of ss 8 and 25 of the Evidence Act 2006. The paper concludes that the current interpretation of s 25 would not enable resolution of the issue. However a wider interpretation of ‘reliability’ would allow a finding that exclusion percentages are inadmissible, in keeping with a focus on fairness to the defendant.