poor quality of the video meant that the jury was left to speculate on an important issue for both parties, rather than
equipped to make a fully informed decision on a subject beyond
 At the gatekeeping stage, the appellant contends that the
trial judge failed to factor into his cost-benefit analysis that this
was evidence tendered by the defence, not by the prosecution. As
a result, the trial judge failed to consider two important factors:
( i) that in balancing probative value and prejudicial effect,
defence evidence may only be excluded where the prejudicial
effect of the proposed evidence substantially outweighs its
probative value; and
( ii) that the rules of evidence are to be applied more flexibly
where the proponent of the evidence is the defence.
These omissions, the appellant argues, are fatal to the trial judge’s
decision to exclude the evidence.
 The respondent rejects the claim of error advanced by the
appellant. The trial judge got it right. At both steps or stages of
 At the threshold stage, the respondent says, the proposed
evidence was neither relevant nor necessary. Dr. Harlow acknowledged that, in light of his (unreliable) assumptions, the white
glint could well have been the chain and medallion. This tepid
conclusion lacked sufficient relevance to assist the jury in resolving the core issue of identification of the shooter. On the issue of
identification, the jury was not in need of expert assistance
on this single aspect of the identification when their conclusion
required a reasoned assessment of the cumulative effect of several
identifiers all of which pointed to the appellant.
 The respondent says the fatal flaw in the proposed evidence was that it was laden with many of the detrimental indicia associated with expert evidence. It was apt to distract the
jury from its fundamental task of determining on all the evidence whether the Crown had proven beyond a reasonable
doubt that the appellant was the shooter. Its potential effect on
the jury exceeded its reliability as probative material. And in the
end, it was an opinion that ventured beyond its author’s area
 As for the gatekeeper function, the respondent continues,
the trial judge was obviously aware that the proponent of the evidence was defence counsel, not the Crown. Nothing said or left
unsaid in the trial judge’s reasons reflects an error of law or
of principle, or any material misapprehension of the evidence.