Stuart O'Connell Criminal Law Blog

Qualifying the Expert Witness For expert evidence to be admissible the expert must be properly qualified.    The party who tenders the witness as an expert is required to demonstrate that the witness has acquired a special knowledge of a particular topic by formal study, practical experience, or both, which extends beyond that of the trier of fact. The competence of the witness to give expert evidence, or to be qualified as an expert, does not depend on how the skill was acquired, only that it has been gained. Justice Watt, Manual of Criminal Evidence , 2013 at pg. 428.   Deficiencies in an expert’s opinion go to weight, not admissibility. R. v. Marquard , 1993 CanLII 37 (SCC) at pg. 224. Additionally, in order for the expert to be properly qualified, the expert must be willing and able to fulfil the expert's duty to the court to provide evidence that is: i. Impartial, ii. Independent, and `        ...

The modern Canadian law on the admissibility of expert evidence began with the judgment of Sopinka J. in R. v. Mohan , [1994] 2 S.C.R. 9. But in the last two decades since Mohan was decided the law on expert evidence has changed significantly. The test in White Burgess is now the governing test for the admissibility of expert evidence. It adopts a two-stage approach: the first stage focuses on threshold requirements of admissibility; the second stage focuses on the trial judge’s discretionary gatekeeper role. Each stage has a specific set of criteria.  STAGE ONE:   Threshold Requirements for Admissibility Expert evidence is admissible when It meets the threshold requirements of admissibility, which are: a.    The evidence must be logically relevant; b.   The evidence must be necessary to assist the trier of fact; c.    The evidence must not be subject to any other exclusionary rule; d.    The...