R v Sekhon, 2014
SCC 15 (20 February 2014) is interesting on when an expert’s opinion has no
probative value, and on the appellate court’s approach to assessing the
inevitability of a guilty verdict.
An expert
witness said that in his extensive experience drug couriers always know that
they are in possession of a drug. They are not “blind” couriers. The material
issue was the defendant’s knowledge of the presence of a drug in the vehicle he
drove at the Canadian border.
The expert’s
evidence here cannot readily be reduced to the necessary logical proposition
that constitutes the likelihood ratio that expresses probative value.
To determine
probative value it is necessary to know whether the evidence is more consistent
with the defendant’s guilt than with the defendant’s innocence.
At first
blush it seems that this evidence is indeed of that kind: it carries the
implication that the defendant must have known of the presence of the drug. But
that, without more, is fallacious, for it is simply saying that other
defendants in other cases have known of the presence of the drug, so this
defendant must have known too.
To determine
whether the evidence is more consistent with the defendant’s guilt than with
the defendant’s innocence, one asks how likely it is to have been obtained on
the assumption that the defendant is guilty, compared to how likely it is to
have been obtained on the assumption that the defendant is innocent.
Here the
expert’s opinion doesn’t fit into that formula. If the opinion comes down to
saying “the defendant knew the drug was present”, it is conclusory not
probative.
This sort of
analysis is important, for at trial there was no objection to the evidence
being given. Not only did counsel not object to it, but at this judge-alone
trial the judge accepted it, and the British Columbia Court of Appeal majority
(Newbury JA dissenting) also thought it was admissible. But all the Supreme
Court judges in Sekhon held that the
expert’s opinion was not admissible [49] – [50], [61], [75] – [76], [79] – [80].
The other interesting aspect of Sekhon is the split in the Supreme Court over whether this was a case in which the conviction could be upheld by application of the proviso. This sort of split arises from different evaluations of the strength of the prosecution case as it would have been if the inadmissible evidence hadn’t been given. Here the trial judge gave a reasoned decision, so it should have been relatively easy to evaluate the strength of the case without the impugned evidence. Jury trial convictions are, broadly speaking, more easily overturned when inadmissible evidence was led at trial, because the appellate court cannot examine the reasoning of the jury and there are more live possibilities for how the reasoning may have proceeded in the absence of the error. Differences in appellate perceptions of the significance of such errors at trial point to a weakness in the criteria for deciding conviction appeals.
The other interesting aspect of Sekhon is the split in the Supreme Court over whether this was a case in which the conviction could be upheld by application of the proviso. This sort of split arises from different evaluations of the strength of the prosecution case as it would have been if the inadmissible evidence hadn’t been given. Here the trial judge gave a reasoned decision, so it should have been relatively easy to evaluate the strength of the case without the impugned evidence. Jury trial convictions are, broadly speaking, more easily overturned when inadmissible evidence was led at trial, because the appellate court cannot examine the reasoning of the jury and there are more live possibilities for how the reasoning may have proceeded in the absence of the error. Differences in appellate perceptions of the significance of such errors at trial point to a weakness in the criteria for deciding conviction appeals.
