The recent Ontario Land Tribunal (OLT) decision 413464 Ontario Limited v. City of Windsor reiterates the ‘four-part’ test for consideration of any expert witnesses’ opinions as detailed by the Supreme Court of Canada in R. v. Mohan [1994] 2 S.C.R. 9. The four threshold requirements that must be established for the expert opinion evidence to be admissible are:
- relevance;
- necessity in assisting the trier of fact;
- absence of an exclusionary rule; and
- a properly qualified expert.
In cases where the four threshold requirements are met, trail judges can determine that evidence is inadmissible when the probative value is overborne by its prejudicial effect.
With reference to the Supreme Court of Canada’s decision in White Burgess Langille Inman v. Abbott and Haliburton Co. [2015] 2 S.C.R. 182, the Tribunal clarifies that “the OLT will not adjudicate on specific issues of professional conduct or professional negligence or make specific rulings as to whether any expert has complied with any applicable rules of conduct or standards of practice”. This is separate and apart from opposing expert reports or witness statements, which are often responded to, and may include critiques relating to professional standards or rules without turning an OLT proceeding into a professional disciplinary hearing.