Experts - Non-Opinion Evidence. R v Sheriffe
In this criminal case, R v Sheriffe (Ont CA, 2015), the Court of Appeal made the interesting and useful point that an expert witness is entitled to give non-opinion testimony if it is otherwise admissible:
 A final point has to do with the capacity of an expert to give evidence of firsthand observations that she or he makes that may be relevant to issues at trial. The opinion rule does not bar an expert from giving evidence of fact: Abbey 1982, at p. 42. Put another way, an expert is not confined by the opinion rule to expressing opinions only. The expert is entitled to give evidence of firsthand observations, including for example, those made during a psychiatric interview by a psychiatrist called to proffer an opinion on criminal responsibility.