Drawing the Line between Lay and Expert Opinion Evidence

53 Pages Posted: 12 Jun 2017  

Jason Michael Chin

The University of Queensland - T.C. Beirne School of Law

Jan Tomiska

University of Toronto

Chen Li

University of Toronto

Date Written: June 7, 2017

Abstract

This article examines the vanishingly thin line between lay and expert opinion evidence in Canada. In Parts I and II, we set the stakes. Canadian trial courts have been warned by peak scientific bodies and public commissions like the Goudge Inquiry about the dangers of attorning to persuasive expert witnesses. Thus, expert evidence faces new hurdles, both substantively and procedurally. This scrutiny has inspired parties to seek refuge in the more flexible and discretionary lay opinion evidence rules. But newfound vigilance to expert opinion is invalidated if the same evidence can be admitted as lay opinion. Parts III and IV illustrate this problem as we examine three cases in which authoritative lay witnesses opined on topics requiring specialized training and expertise. Three hazards are readily apparent from this analysis: (1) the lay witnesses opined on matters in which there are established methodologies to control for unconscious bias, but did not follow these methodologies; (2) the lay witnesses – police officers – were authority figures but were not qualified as experts in the area they were opining on, and; (3) the lay opinion jurisprudence has failed to meaningfully distinguish between lay and expert opinion. In Part V we seek to fill this void by proposing a new analytic approach – Lay Opinion 2.0 – which draws on both the practical and epistemological distinction between lay and expert opinion to provide an efficient and fair test for the admission of lay opinion evidence.

Keywords: Lay Opinion, Lay Evidence, Lay Opinion Evidence, Expert Opinion, Expert Opinion Evidence, Psychology and Law, Scientific Evidence, Forensic Evidence, R v Graat, R v Mohan, Daubert

JEL Classification: K14, K41

Suggested Citation

Chin, Jason Michael and Tomiska, Jan and Li, Chen, Drawing the Line between Lay and Expert Opinion Evidence (June 7, 2017). McGill Law Journal, Vol. 63, No. 1, Forthcoming . Available at SSRN: https://ssrn.com/abstract=2982750

Jason Michael Chin (Contact Author)

The University of Queensland - T.C. Beirne School of Law ( email )

The University of Queensland
St Lucia
4072 Brisbane, Queensland 4072
Australia

Jan Tomiska

University of Toronto ( email )

Department of Statistical Sciences
Toronto, Ontario M5S 3G8
Canada

Chen Li

University of Toronto ( email )

Department of Statistical Sciences
Toronto, Ontario M5S 3G8
Canada

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