Evidence - Expert Opinion - Profiling. R v Solleveld
In R. v Solleveld (Ont CA, 2014) the Court of Appeal discusses at length the principles applicable to the admission of expert opinion evidence, including when expert opinion evidence amounts to 'profiling' (over-generalizing by an expert):
 Mr. Dineen submits that to the extent Byrne [SS: the expert witness] testified that the documents and methods used by the appellants were typical of those used by fraudsters and indicated a fraudulent intent, it should not have been admitted.
 First, it is submitted that such evidence amounts to profiling and second, such evidence usurps the role of the jury to determine whether the appellants had the requisite intent for the offence of fraud.
 Reliance is placed on R. v. Sekhon, 2014 SCC 15, at para. 46:
Given the concerns about the impact expert evidence can have on a trial — including the possibility that experts may usurp the role of the trier of fact — trial judges must be vigilant in monitoring and enforcing the proper scope of expert evidence. While these concerns are perhaps more pronounced in jury trials, all trial judges — including those in judge-alone trials — have an ongoing duty to ensure that expert evidence remains within its proper scope. It is not enough to simply consider the Mohan criteria at the outset of the expert’s testimony and make an initial ruling as to the admissibility of the evidence. The trial judge must do his or her best to ensure that, throughout the expert’s testimony, the testimony remains within the proper boundaries of expert evidence. As noted by Doherty J.A. in R. v. Abbey, 2009 ONCA 624 (CanLII), 2009 ONCA 624, 97 O.R. (3d) 330, at para. 62: Sekhon involved the evidence of a police officer who testified that he had never encountered a drug courier who was blind to the fact that he or she was carrying drugs. This was held to be inadmissible evidence, at para 49:
The admissibility inquiry is not conducted in a vacuum. Before deciding admissibility, a trial judge must determine the nature and scope of the proposed expert evidence. In doing so, the trial judge sets not only the boundaries of the proposed expert evidence but also, if necessary, the language in which the expert’s opinion may be proffered so as to minimize any potential harm to the trial process. A cautious delineation of the scope of the proposed expert evidence and strict adherence to those boundaries, if the evidence is admitted, are essential. The case law demonstrates that overreaching by expert witnesses is probably the most common fault leading to reversals on appeal. [Emphasis added and citations omitted by S.C.C.]
The fact that [the police officer] did not personally encounter a blind courier over the course of his investigations is neither relevant nor necessary, within the meaning ascribed to those terms by this Court in Mohan, to the issue facing the trial judge — namely, whether Mr. Sekhon himself had knowledge of the drugs. The Impugned Testimony, though perhaps logically relevant, was not legally relevant because the guilt or innocence of accused persons that [the police officer] had encountered in the past is legally irrelevant to the guilt or innocence of Mr. Sekhon (see Mohan, at pp. 20-21). In other words, the Impugned Testimony was of no probative value in determining whether Mr. Sekhon knew about the cocaine in the hidden compartment. It is trite to say that a fundamental tenet of our criminal justice system is that the guilt of an accused cannot be determined by reference to the guilt of other, unrelated accused persons. Moreover, the Impugned Testimony was not necessary because determining whether Mr. Sekhon knew about the drugs is not beyond the knowledge and experience of the judge, and it is certainly not a matter that is technical or scientific in nature. [Emphasis in original.] In our view, Professor Byrne’s evidence does not amount to the kind of profiling evidence precluded by Sekhon.
 The admission of Byrne’s evidence met the four criteria set out in R. v. Mohan, 1994 CanLII 80 (SCC),  2 S.C.R. 9: i) relevance, ii) necessity in assisting the trier of fact, iii) the absence of any exclusionary rule, and iv) a properly qualified expert. The appellants do not challenge the qualification of Professor Byrne, nor are there any applicable exclusionary rules. The evidence as to the nature and character of the methods and documents used by the appellants was plainly relevant to the issue of whether or not their investment scheme was a fraudulent scam. In our view, the evidence was also necessary given the inherent complexity of international banking and the esoteric nature of documents used by the appellants to attract investors. International banking practices and purportedly sophisticated and obscure investments of the kind used by the appellants are not matters within the knowledge and experience of the ordinary juror. Professor Byrne had specialist knowledge that could assist the trier of fact in understanding the obscure terminology and jargon of the financial world.
 Professor Byrne’s analysis of the document and methods used by the appellants did not, as in Sekhon, depend for its relevance on “the guilt or innocence of accused persons that [the witness] had encountered in the past” but rather upon Byrne’s expert knowledge of international banking and the types of documents that are properly and improperly used in that highly specialized sphere of activity.