Are credibility assessments relevant in a summary judgment motion?

Whether credibility assessments have any place in a summary judgment motion was dealt with squarely in Masciangelo v. Spensieri (1991), 1 C.P.C. (3d) 124. Doherty, J. noted, “arguments which involve the central facts of the case and turn on judgments as to credibility should not be resolved on a R. 20 motion.” However, he was clearly concerned with the most obvious form of factual dispute: …a disagreement as to the primary facts which are at the heart of the lawsuit, the resolution of which requires an assessment of the credibility of the competing parties and a choosing between two diametrically opposed versions of the main events. [emphasis added]