Effectively Using Experts In IP Litigation – Part 1: Theory

In IP litigation, expert testimony is common and important. Experts may provide the court with a scientific primer in highly complex cases. In patent litigation, experts may construe complex claims through the eyes of a person skilled in the art, assess whether claimed subject matter was anticipated or obvious, or conduct tests to show infringement. In trademark cases, experts may conduct surveys to assess reputation or likelihood of confusion. For remedies, experts may model the marketplace or calculate the amount of damages suffered or profits earned as a result of infringement. The outcome of many high stakes IP cases has turned on expert testimony. It is therefore vital for every IP litigator to understand how to effectively use experts in their cases.

This article (the first of a two-part series) focuses on the more theoretical aspects of expert testimony: their role, the test for admissibility and some procedural considerations. The next article will focus on more practical aspects: selecting experts, drafting expert reports, and preparing experts for cross-examination.

The role of an expert: Fair, objective, and non-partisan assistance

The role of an expert is to assist the court, not to advocate. In White Burgess Langille Inman v Abbott and Haliburton Co, 2015 SCC 23, the Supreme Court of Canada noted that experts "have a special duty to the court to provide fair, objective and non-partisan assistance."

The Federal Court has codified this special duty in the Code of Conduct for Expert Witnesses, which states that experts owe a general duty to assist the Court impartially on matters relevant to their area of expertise. Some provinces, including Ontario and Quebec, have adopted similar rules. Experts who fail to comply with this special duty may have their evidence excluded or given little weight (for example, see Federal Court Rule 52.2(2) and Alfano v Piersanti, 2012 ONCA 297).

The admissibility of expert testimony: Four requirements

In R v Mohan, [1994] 2 SCR 9, the Supreme Court of Canada set out the following four requirements for admissibility of expert evidence:

Relevance to a material issue; Necessity in assisting the trier of fact, namely whether the evidence is likely to be outside the experience and knowledge of the judge; The absence of any exclusionary rule (expert evidence cannot be used to circumvent other rules of evidence); and A properly qualified expert. In Masterpiece Inc v Alavida Lifestyles Inc, 2011 SCC 27, the...