By Rachel Rogers and Susan VanderPlas

We investigate how the use of bullet comparison algorithms and demonstrative evidence may affect juror perceptions of reliability, credibility, and understanding of expert witnesses and presented evidence. The use of statistical methods in forensic science is motivated by a lack of scientific validity and error rate issues present in many forensic analysis methods. We explore what our study says about how this type of forensic evidence is perceived in the courtroom – where individuals unfamiliar with advanced statistical methods are asked to evaluate results in order to assess guilt. In the course of our initial study, we found that individuals overwhelmingly provided high Likert scale ratings in reliability, credibility, and scientifically regardless of experimental condition. This discovery of scale compression - where responses are limited to a few values on a larger scale, despite experimental manipulations - limits statistical modeling but provides opportunities for new experimental manipulations which may improve future studies in this area

Journal of Data Science; Volume 22, Issue 2, 2024, 19p.

By Scottish Government, Safer Communities Directorate

Summary

• Research shows further evidence on the negative impact of rape myths and misconceptions on the complainer, but also raises concerns about perceived fairness by legal professionals when using single judge trials.

• Overall, there is a lack of empirical research comparing modes of trial for rape cases, which makes it difficult to draw any robust conclusions in relation to their impact on the complainer, rights of the accused, public confidence in the justice system and conviction rates.

• That said, there are some tentative indications that the complainer experience may be improved by a single judge trial model, but it might be more dependent on wider court procedures and approaches to (cross) examination than the mode of trial itself.

• Providing a written reason of verdict is seen as a clear advantage of single judge trials, both for the complainer and accused.

• Studies suggest that considering the rights of the accused should include agreeing on the justifications/criteria for single judge trials, establishing clear procedures to ensure consistency and transparency and addressing (implicit) bias and diversity in the judiciary.

• Significantly, where single judge trials for serious offences have been adopted, e.g. in countries such as New Zealand, Australia, Canada and the United States, it is by choice of the accused. There were no instances found of jurisdictions introducing alternatives to jury trials specifically for rape cases.

• There is no clear data on the effect of changing mode of trial on public confidence in justice system, although studies have shown a clear support of the public for the jury system. These studies however, did not ask directly about changing mode of trial in specific cases, such as for rape offences.

• The evidence is mixed on conviction rates, from lower, to no difference, to higher rates of conviction for cases tried by single judge, although, again, the evidence is limited and not specific to rape cases.

• Literature discussing mixed panels of professional and lay judges point to the possibility to mitigate concerns about the lack of community engagement and potential bias with one decision-maker, while preserving some of the advantages of a single judge trial such as clearer judicial direction and a reasoned written verdict.

• Overall, the literature suggest that to understand the impact of a change in mode of trial, it is important to take into account how a new mode of trial interacts with already established procedures in the criminal justice system. To improve the complainer experience additional reflection would be required on pre-trial and cross-examination procedures and training given to legal professionals.

• Taking into account that the evidence presented is limited and not always specific to sexual offences, it is difficult to make a clear translation to the context of a Scottish pilot for rape offences. A pilot can offer valuable and much needed empirical data and insight on the effects of a change in mode of trial.

Edinburgh: Scottish Government Safer Communities Directorate, 2023. 40p.