Expert Independence

Do the new rules pertaining to expert evidence impose a higher duty than at common law?  When an expert is alleged to be biased due to a connection to one of the parties or a matter in issue, does it go to admissibility or weight? 

In Henderson v. Risi, 2012 ONSC 3459 (S.C.J.), the defendant proffered an expert, Mozessohn, to give testimony at trial regarding irregularities in the financial records of Timeless Inc., provide an opinion on the value of shares in Timeless held by the plaintiff, and critique the plaintiff expert's opinion.  The plaintiff objected to the admissibility of Mozessohn's evidence on the basis that he was not independent or impartial since he was a partner in the accounting firm that acted as Timeless' Trustee in Bankruptcy.  Mozessohn testified that there had been no communication between members of his firm about the case.

Justice Lederman quoted the Newfoundland Court of Appeal in Gallant v. Brake-Patten 2012 NLCA 23 (CanLII), which summed up the law regarding the admissibility of expert evidence where the allegation is the expert lacks institutional independence as opposed to personal advocacy:

In summary, in civil cases, if expert evidence meets the Mohan criteria for admissibility, it is admissible.  Bias or partiality in expert evidence which is based on the expert having a connection with a party or issue or a possible pre-disposition or approach in the case is a reliability issue which is best determined when the whole of the expert evidence is considered in the context of all of the trial evidence.  As such, the issue is one of weight and not admissibility.

Plaintiff's counsel argued that the new r. 4.1 and the changes to r. 53 imposed a higher level on duty on an expert in Ontario, and that the question of institutional independence must be determined at the admissibility stage rather than leaving it to be considered as a matter of weight.

Justice Lederman disagreed and allowed the expert to give testimony.  Rules 4.1 and 53 simply remind experts of their already existing obligations to provide opinion evidence that is fair, objective and non-partisan.  Any lack of institutional independence went to weight rather than admissibility.  The new rules impose no higher duties than already existed at common law.