Comparing jury focus and comprehension of expert evidence between adversarial and court-appointed models in Canadian criminal court context

Abstract

The present adversarial system is often criticised for not working as well as it should in the area of expert scientific testimony. Yet scientific opinion evidence is an important aspect of present criminal trials. In addition to issues in the provision of expert evidence, triers of fact are challenged to understand complex scientific evidence. Several dynamics are at play that may impact on their ability to focus on and comprehend the science, and alternative models have been suggested to address these issues, including the use of court-appointed experts. This study examines juror focus on the science versus the persona/demeanour of the expert witness between the adversarial and court-appointed models for presentation of scientific evidence. Findings suggest that expert persona/demeanour continues to be a large focus area for jurors, that the CA model may be more resilient for ensuring greater focus on science, and that juror comprehension of science is somewhat better when presented via the court-appointed model. Results inform instruction of experts for giving opinion evidence as well as suggest the prudence of considering other models to improve the criminal justice system. Limitations as to the generalization of study results are discussed.

RÉsumÉ

Le système contradictoire courant est souvent critiqué pour ne pas fonctionner aussi bien qu'il le devrait en matière de témoignages d'experts scientifiques. Cependant, la preuve par opinion d'expert est un aspect important lors des procès en droit criminel. Outre les enjeux des témoignages d'experts, les juges des faits sont mis au défi de comprendre la preuve scientifique parfois complexe. Plusieurs éléments peuvent intervenir, lesquels peuvent avoir un impact sur la capacité des juges de concentration et de compréhension de la preuve scientifique. Des modèles alternatifs sont suggérés afin de remédier au problème, dont un système de nomination d'experts par les tribunaux. La présente étude examine la concentration du jury sur la science par opposition au personnage et au comportement des témoins experts entre le modèle contradictoire et le modèle de nomination pour la présentation de la preuve scientifique. Nos résultats suggèrent que le comportement des témoins experts continue à être un domaine d'intérêt pour les jurés, que le système canadien peut être plus résistant afin d'assurer davantage une concentration sur la science et que la compréhension du jury de la science est quelque peu améliorée lorsque présentée dans un modèle de nomination par les tribunaux. Les résultats suggèrent des enseignements aux témoins experts lorsqu'ils donnent leur opinion ainsi que le discernement de prendre en considération d'autres modèles afin d'améliorer le système de justice canadien. Les limites de cette étude sont examinées ci-après.

Keywords:

• Jury
• forensic science
• adversarial
• court-appointed
• expert evidence

Mot-clés:

• jury
• science légal
• contradictoire
• tribunal nomme (avocat commis d'office)
• évidence d'expert

Acknowledgments

The researchers want to thank: the late Dr. Rory Coughlin for his advice and support with research methodology; Professor Paul Atkinson for his ongoing support with research students; all of the volunteers who helped create the videos for jury viewing, especially those who played the role of expert; and especially Professor Anna Cappelli who performed the expert role twice. We also thank all of the students who participated as mock jurors.

Disclosure statement

The researchers declare no relationship or financial support from commercial interests and no external financial research support received. Research expenses were internally funded by Trent University.

Notes

1 This may be true of technical evidence provided through expert opinion as well. For the purposes of this paper we are focussing on the presentation of scientific evidence. For a more fulsome discussion of the call for change, see Anderson GR, (2) p.499.

2 A thorough discussion of the difference between the inquisitorial and adversarial systems of law is beyond the scope of this paper except as to the extent it informs the research study. For a review of the inquisitorial system specific to expert evidence see Vuille J. Admissibility and appraisal of scientific evidence in continental Europe criminal justice systems: past, present and future. Aus J For Sci. 45(4):389–397. DOI:10.1080/00450618.2012.738248.

3 Of course, CA and AD experts may be used in conjunction which is often the recommended use in Rules in the United States as elaborated on in Note 10 below. For the purpose of this research we consider the use of one (CA) as a replacement for the use of the other (AD), acknowledging that there are situations where using them in conjunction may be appropriate. In our framing of the options there would be other iterations of the presentation of expert evidence between the two being considered such as expert panels.

4 By comparison, the other prominent legal system used elsewhere in the world is called the Inquisitorial system. Each system has different processes for conducting trials, e.g., in the inquisitorial system, the judge calls the witnesses and is much more active in questioning witnesses, albeit party counsel still play an active role in examinations.

5 Over the years, courts have allowed some “opinion” from non-expert witnesses where the opinion relates to matters within common knowledge (Anderson, p.44).

6 For example, the “NAS” report, as it has come to be known, is critical of the forensic science community and, relevant to this research, indicates that the evidence that forensic scientists sometimes give is exaggerated, subject to contextual bias, and at times fabricated.

7 It should be noted that all expert witnesses, even in the adversarial system, are meant to be impartial and objective and often have to sign oaths to that effect. But, as discussed re: the nature of the biases that exist, when an expert is called by one party only, the impartiality and objectivity can be questionable.

8 For this research we have limited our focus to the juror as trier of fact.

9 Note that the role of a CA expert can be defined differently in the literature and caution needs to be exercised in determining the model of CA being referred. The CA expert can be used as an advisor to the court who does not give testimony, or the CA expert can be used in addition to party-appointed experts. For example, FRE 706 in US, while allowing the use of court-appointed experts, does so more as an addition to party-appointed experts.

10 For the purposes of this research the focus is on the idea of a court-appointed expert because it represents the other extreme from the present adversarial system, as a start to consider implications of application of other models.

11 Note that the idea that a single expert will be neutral is not a universally held belief. For example, see Kennedy M. The problems with court-appointed “independent” experts. http://www.litigatonandtrial.com/2016/04/articles/attorney/frcp-706-independent-experts/ and see also, Champod C, Vuille J. Scientific evidence in Europe – admissibility, evaluation and equality of arms. International Commentary on Evidence, 2011;9(1), ISSN (online).

12 Per section 649 of the Criminal Code of Canada