2. When will the court allow expert evidence?

2. When will the court allow expert evidence? 

The court will not allow expert evidence simply because a party wishes to call an expert. Instead, the court acts as a rigorous “gatekeeper” to ensure that expert evidence is used only when it is reasonably necessary to resolve the issues and provides genuine technical assistance beyond the judge’s existing knowledge. 

In deciding whether expert evidence should be admitted, the court will generally consider three matters: 

1. Necessity: Expert evidence is only permitted when the subject matter falls within a class of subjects, such as science, art, or a specific trade, where a person without special instruction would be unable to form a sound judgment. Expert evidence is not necessary and will be excluded if the court is fully capable of arriving at its own decision by applying ordinary knowledge, common sense, and experience to the proved facts. 

2. Relevance: The evidence must be helpful to the court in arriving at its decision on one or more of the material issues to be resolved. The burden is on the party seeking to adduce expert evidence to demonstrate this relevance to the issues. 

3. Probative value: The court considers whether the evidence has sufficient weight or value to affect the outcome of the case. If the probative value is low or marginal, it may be excluded to save time and costs. 

Further, under the Civil Justice Reform, the court is mandated to actively manage expert evidence to further the underlying objectives of cost-effectiveness, expedition, and proportionality. The court weighs the necessity of the expert against the value of the claim and the importance of the issue, comparing these factors with the significant costs of employing experts.