Expert Evidence (ON)This practice note reviews the role of an expert witness and expert opinions in a proceeding. It reviews the expert's duty to the court, the process and criteria for choosing an appropriate expert witness, and the maximum number of experts in a proceeding. This practice note also outlines what must be included in an expert report (including the rules on medical expert reports), rules respecting draft reports, and when expert reports must be served. It reviews specific issues with respect to expert evidence, including hearsay evidence, statistical evidence, novel or contested science evidence, social science evidence, surveillance evidence, the evidence of a deceased expert, and hypothetical questions. Finally, this practice note outlines the test for the admissibility of expert evidence at trial and the process for adducing expert evidence at trial, including the scope of the expert's testimony.