Trial judge proper person to decide admissibility of evidence

Harrop v. Harrop, 2010 ONCA 390, released today, affirms a Divisional Court decision that the trial judge ought to determine what is, or is not, proper evidence for trial. The case is limited to expert evidence but presumably has relevance for all types of evidence -- for example, whether a witness properly summoned, has relevant and material evidence to give.

The Court holds:

[1] The issue in this case is whether a motion judge can decide on the admissibility of proposed expert evidence.

[2] In our view, the policy considerations relevant to this issue all point to the trial judge determining this question. It avoids the risk of a multiplicity of proceedings in any given case. It ensures a full context in which the decision can be made. It avoids the risk of preliminary steps being taken for purely tactical reasons. And it avoids creating different appeal rights depending on whether the decision is made by a motion judge as an interlocutory order or the trial judge.

[3] Thus, even if a motion judge has such jurisdiction, it should be exercised only in the rarest of cases. Nothing has been shown to us to put this case in that category.