Pre-recorded evidence does not affect jury decisions, research suggests

There is no compelling evidence that the use of pre-recorded evidence or live links, whether by child or adult witnesses, has an effect on verdict outcomes in (mock) criminal trials, according to two related research papers published by the Scottish Government today.

The Impact of the Use of Pre-Recorded Evidence on Juror Decision-Making: An Evidence Review, and The Impact of the Use of Pre-Recorded Evidence on Juror Decision-Making: An Evidence Review - Research Findings, both authored by Professor Vanessa Munro of the University of Warwick, summarise and evaluate existing evidence on the impact on juror decision-making of the use of such testimony in criminal trials across a range of legal jurisdictions.

The former report is a summary and the latter a fuller discussion of the available material.

Drawing on international evidence from simulated or "mock" jury experiments, which are the de facto method for studying jury decision making, they find that in respect of child witnesses, individual jurors may harbour a preference for evidence delivered live and in person. However, the evidence suggests that this preference does not translate in any consistent or reliable way into (mock) juror verdict outcomes.

In respect of adult witnesses, the evidence base is more limited, but a number of robust studies in Australia and England indicate that the use of pre-recorded evidence or live links by adult female rape complainers does not significantly influence (mock) jurors’ evaluations and verdicts. The position in respect of adults in other trials is less clear, and requires further investigation, but there is not as yet compelling evidence of a verdict impact on (mock) jury decision making.

The reports highlight a number of operational factors which may influence jurors, such as the length and format of forensic interviews, audio and visual quality of evidence, and camera perspective, which, it is suggested, should be considered when using pre-recorded evidence to avoid undue influence on jurors.