Evaluation of DNA results based on competing activity level propositions has reached prominence in recent years, particularly in respect to addressing challenges frequently raised in court. The approaches scientists employ to address these challenges differ markedly between legal systems, countries and jurisdictions, ranging from Bayesian network to more generic comments on DNA transfer possibilities, where "everything is possible." In light of these discrepancies and the substantial variations observed in reporting officer practices, this study aimed to investigate the attitudes, experiences, and needs of court-going forensic biologists regarding DNA transfer, persistence, prevalence, and recovery (DNA-TPPR) issues.

An international online survey was distributed to reporting practitioners with responses collected from five countries and several laboratories: the United Kingdom (30 responses), Australia (4), Canada (4), New Zealand (7), and the United States (10), resulting in a total of 55 participants. Respondents ranged from early-career scientists to highly experienced caseworkers and managers. The questionnaire combined structured multiple-choice answers to questions (with ranking options) and open-ended prompts, covering reliance on data sources, court trends, specific scenarios encountered, means of reporting, comfort levels in testimony, consultation practices, challenges, and desired future resources across TPPR topics.

Consistent themes and variations emerged across responses. The analysis assessed variations by country, professional experience, and training background in approaches to TPPR evaluations. Respondents highlighted a range of challenges in addressing TPPR questions, alongside diverse perspectives on court trends, comfort levels, and resource needs. Future priorities identified included additional training, improved data resources, and targeted research, with variations based on jurisdictional and professional differences.

While jurisdictional diversity among practitioners is limited, these findings provide an international snapshot of current practices and challenges among reporting scientists. By identifying commonalities and divergences, the data inform targeted research priorities and training and guideline improvements with the ultimate goal of improving the robustness and consistency of activity level evaluations.

Authors

• Mariya Goray (Flinders University, Australia)
• Duncan Taylor (Forensic Science SA, Australia)
• Roland van Oorschot (Victoria Police Forensic Services Department, Australia)