Smith v. Inco, 2012 ONSC 4749:
 The leading case as to the admissibility of opinion evidence fromnon-expert witnesses is that of R. v. Graat, 1980 CanLII 69 (ON CA), (1980) 30 O.R. (2d) 247 (OCA), aff'd1982 CanLII 33 (SCC),  2 S.C.R. 819 (SCC). In that case twopolice officers (non-expert witnesses) testified that in their opinion the accused's ability to drive was impaired by alcohol. This opinion evidence was based upon a list of factual observations made by thepolice officers, including observations that the accused's car was weaving on the roadway, the car crossed the centre line, the car travelled onto the shoulder of the road, the accused's breath smelled of alcohol, and the accused was unsteady on his feet after exiting the vehicle.
 The trial judge admitted the opinion evidence of these two officers at the trial, and the accused was convicted. Appeals to the County Court and the OCA were dismissed. At the Supreme Court of Canada ("SCC"), in the decision cited above, the Court confirmed that the evidence of the two officers was admissible as evidence of impairment by alcohol.
 At page 824 of the SCC decision, the Court approved of a statement made by the OCA that admissible opinion evidence fell into two traditional categories: (1) expert opinion evidence on matters requiring specialized skill and knowledge, and (2) non-expert opinion evidence on matters requiring no special knowledge, where it is virtually impossible to separate the witness' inference from the facts on which the inference is based.
 On the same page, the SCC also adopted comments made by the OCA that the admission of opinion evidence in the latter category was merely a compendious way of ascertaining the result of the witness' observations.
 At page 835 the SCC provided a non-exhaustive list of subjects upon which non-expertwitnesses were permitted to give opinion evidence, including the identification of handwriting, persons and things, apparent age, the bodily plight or condition of a person, the emotional state of a person, the condition of things, questions of value, and estimates of speed and distance.
 Further, at page 837 the SCC adopted a statement from Professor Cross that in cases where "the facts from which awitness received an impression were too evanescent in their nature to be recollected, or too complicated to be separately and distinctly narrated", awitness may be permitted to state his opinion or impression.
 In summary, theGraat case stands for the proposition that opinion evidence from a non-expert witness is admissible if the opinion is one that does not require any specialized skill or knowledge, and the opinion is grounded in the factual observations of the witness, and the opinion is actually a compendious way of ascertaining thewitness' observations.