Generally opinion evidence is only admissible at trial by a duly qualified expert. One exception to this rule relates to lay witnesses being able to provide a Court with opinions in limited circumstance. Reasons for judgement were released this week by the BC Supreme Court, Vancouver Registry, discussing this exeption.
In this week’s case (American Creek Resources Ltd. v. Teuton Resources Corp.) the litigants were involved in a commercial dispute. In the course of trial the President of the Defendant company wished to provide the Court with certain opinions. In addressing this Mr. Justice Grauer provided the following summary of the boundaries of lay opinion evidence:
 Generally, opinion evidence is inadmissible unless it is expert evidence. There are exceptions. Lay opinion evidence may be admissible under circumstances discussed at length in Part II of Chapter 12 in The Law of Evidence in Canada, where the learned authors state at paragraph 12.14:
Courts now have greater freedom to receive lay witnesses’ opinions if: (1) the witness has personal knowledge of observed facts; (2) the witness is in a better position than the trier of fact to draw the inference; (3) the witness has the necessary experiential capacity to draw the inference, that is, form the opinion; and (4) the opinion is a compendious mode of speaking and the witness could not as accurately, adequately and with a reasonable facility describe the facts she or he is testifying about. But as such evidence approaches the central issues that the courts must decide, one can still expect an insistence that the witnesses stick to the primary facts and refrain from giving their inferences. It is always a matter of degree. As the testimony shades towards a legal conclusion, resistance to admissibility develops.
 I observe that the central issue in this case is whether the expenses claimed by the plaintiff constitute “exploration expenditures”. The defendant takes the position that certain drill patterns employed by the plaintiff do not reflect exploration within the meaning of the agreement, so that the expenses for that portion of the drilling cannot be claimed as constituting “exploration expenditures”. Accordingly, as stated in the excerpt quoted above, it is proper to insist that the witnesses stick to the primary facts and refrain from giving their inferences in relation to that issue.
 But that is not the only basis for such insistence. The proffered evidence does not otherwise meet the required test. In Graat, the Supreme Court of Canada ruled admissible lay opinion evidence about whether a person’s ability to drive was impaired by alcohol. The witnesses in question all had an opportunity for personal observation, and the opinion was based on perceived facts as to the manner of driving and the indicia of intoxication of the driver. These witnesses were in a better position than the trier of fact to determine the degree of impairment and could give the court real help. The court noted at pages 837-838:
It is well established that a non-expert witness may give evidence that someone was intoxicated, just as he may give evidence of age, speed, identity or emotional state. This is because it may be difficult for the witness to narrate his factual observations individually. Drinking alcohol to the extent that one’s ability to drive is impaired is a degree of intoxication, and it is yet more difficult for a witness to narrate separately the individual facts that justify the inference, in either the witness or the trier of fact, that someone was intoxicated to some particular extent. If the witness is to be allowed to sum up concisely his observations by saying that someone was intoxicated, it is all the more necessary that he be permitted to aid the court further by saying that someone was intoxicated to a particular degree. … Nor is this a case for the exclusion of non-expert testimony because the matter calls for a specialist. It has long been accepted in our law that intoxication is not such an exceptional condition as would require a medical expert to diagnose it. An ordinary witness may give evidence of his opinion as to whether a person is a drunk. This is not a matter where scientific, technical, or specialized testimony is necessary in order that the tribunal properly understands the relevant facts. Intoxication and impairment of driving ability are matters which the modern jury can intelligently resolve on the basis of common ordinary knowledge and experience. The guidance of an expert is unnecessary.
 It seems to me readily appreciable from Justice Dickson’s discussion in Graat that the contemplated parameters of admissible lay opinion evidence do not extend to the sort of circumstances I am considering here. The application of the factors discussed in The Law of Evidence in Canada confirms this. Those factors begin with the proposition that the evidence consists of inferences drawn from observed facts, and end with the factor that the opinion is a compendious mode of speaking that allows the witness to sum up more accurately and adequately the facts he or she is testifying about. Thus, “intoxicated” compendiously covers a number of observed facts including such things as staggering, smelling of alcohol, being red-faced and slurring words, all of which may have formed the basis for the inference of intoxication, and all of which can be explored in cross-examination as the sort of observations commonly understood as indicia of intoxication.