On March 26, 2015, the Ontario Court of Appeal released its much anticipated decision in Westerhof v. Gee Estate, 2015 ONCA 206, clarifying the law with regard to the scope of Rule 53.03 and expert witnesses.

Briefly – the Divisional Court previously held that it is the type of evidence to be given that dictates whether a witness must comply with Rule 53.03.  If opinion evidence is to be given, then the witness must comply.  If merely factual evidence is to be given, then no need to comply.

The problem with the Divisional Court’s ruling was that it created uncertainty regarding whether a treating physician, such as a plaintiff’s family doctor, could testify with regard to his or her opinions on diagnosis, ability to work, prognosis, etc.  The result of the Divisional Court ruling was that a treating physician could not provide opinion evidence without first complying with Rule 53.03, such as by completing a Rule 53 compliant report and signing a Form 53.   In practice, that is easier said than done. 

Based on the Divisional Court’s ruling, without Rule 53.03 compliance a treating doctor would be restricted to testifying about their observations of, and history taken from, their patient and, in limited circumstances, about their diagnoses if such diagnoses are only meant to explain the basis for further treatment given.  In such circumstances, the diagnosis would not be opinion evidence tendered for the truth of its contents but would instead be treated as part of the narrative to explain the basis for treatment provided.   Moreover, unless a treating physician was Rule 53.03 compliant, his or her opinions could not be relied on as the evidentiary foundation for the opinions of a Rule 53.03 compliant expert.  This has resulted in absurdities and relevant and probative evidence being deemed inadmissible.

The ONCA has now held that the Divisional Court erred in its reasoning.  The ONCA held that participant experts (such as treating physicians) and non-party experts (such as an Accident Benefits IME Doctor) may give opinion evidence without complying with Rule 53.03.

The ONCA held that the type of evidence to be given (fact vs. opinion) is not the dictating factor to determine whether Rule 53.03 applies.  Rather, the Court held that “a witness with special skill, knowledge, training, or experience who has not been engaged by or on behalf of a party to the litigation may give opinion evidence for the truth of its contents without complying with rule 53.03 where:

  1. The opinion to be given is based on the witness’s observation or participation in the events at issue; and
  2.  The witness formed the opinion to be given as part of the ordinary exercise of his or her skill, knowledge, training and experience while observing or participating in such events.”

Such witnesses should not be designated as “fact witnesses” and, for clarity, should instead be called “participant experts”.  The same reasoning also applies to non-party experts (such as AB IME doctors).

The ONCA further held that if a participant expert or non-party expert offers opinion evidence extending beyond the aforesaid limits, then he or she must comply with Rule 53.03 with regard to the portion of his or her evidence extending beyond those limits.  That essentially means that any opinion evidence given that is not based on the expert’s own observations while observing or participating in the events at issue must comply.   So – for example – suppose a treating neurologist were asked to comment on a patient’s non-neurological issues, such as psychiatric functioning.  Aside from the obvious that the neurologist probably wouldn’t qualify to give expert psychiatry evidence, he or she would have to comply with Rule 53.03 to even attempt to provide an expert psychiatry opinion since he or she likely did not see the patient in relation to psychiatric needs but only for a neurology consult.