What is the test for habituated professional experience?

The notion of “habituated professional experience” as qualification arose in Wilson v. Swanson, 1956 CanLII 1 (SCC), [1956] S.C.R. 804. In that case, a general practitioner purported to provide an opinion on the care and judgment exercised by a surgeon when the general practitioner had no special standing or competence in any medical question raised in the case. His evidence as to what he would have done was of no benefit when his views were based upon what a local surgeon told him what he would have done and the expert admitted to having no views of his own on the question (at 809). Rand J., writing for himself and Nolan J., concluded (at 809) in these circumstances that the expert’s opinion was a “… matter of textbook or verbalized knowledge unsupported by habituated professional experience”. The expert was a “virtual stranger to the exercise of such a medical and surgical judgment” and his was a “collection of elementary views” (at 811). This was one of the different stories because the expertise was minimal.