What is the test for obtaining an expert opinion in a personal injury case?

[48] Accordingly, I conclude that the proposed opinion evidence is not necessary in the sense that it would provide information “which is likely to be outside the experience and knowledge of a judge or jury.” It follows from what I have said, that I also conclude the matters are not so “technical” in nature that they require an expert opinion to “enable the trier of fact to appreciate” them. And, finally, for all the reasons I have stated, I have concluded that “ordinary people” are not unlikely to form a correct judgment without the assistance of the proposed opinion. Therefore, the opinion evidence that mother’s counsel seeks to elicit also fails to meet the second criterion in The Queen v. Mohan, namely, necessity.