Expert Witness


What is an Expert Witness?

An expert witness’ primary job is to deliver his impartial expert opinion based on the material provided. An expert can be used in a variety of settings, including arbitrations, tribunals, and lawsuits.

A witness is someone who gives sworn testimony to a tribunal or court of law. There are basically two types of witness:

Witnesses of Fact who can give evidence of facts but cannot generally give views; Expert Witnesses who can give opinion evidence as well as evidence of facts.

An Expert Witness Will:

In accordance with the instructions, provide an independent expert opinion on the subject matter in their area of knowledge. These directions will be included in the Expert Witness’s Report, which the opposing party and the Court will review.
As needed, provide the opinion in the form of a report and/or evidence before a Court (or other tribunal).


The report is essential since the Expert cannot normally give evidence without it.
Check that the Expert’s Report you receive contains all of the material required by the Court Rules. If you proceed, you must provide a copy of the report to the other party in the dispute. You will be handed a copy of the opposing party’s Expert’s Report at that time.


Follow the applicable procedure rules as well as any Court or tribunal Orders in the matter.


Provide honest, unbiased, and independent opinions, whether or not they support your argument.


An expert witness has a primary obligation to the Court (or other tribunal). This responsibility outweighs any duty owed to you, even if you are still obligated to pay the expert’s fees.


The Court expects expert witnesses to be independent and unbiased, and will disregard evidence from those who are or appear to be political.

An Expert Witness Will Not:

They will not be your advocate and will not uncover evidence or recommend what your case should consist of. It is up to you or your legal counsel to argue your case.


Give any advice outside of their area of expertise.


Offer guidance.


Accept any appointment that entails a potential conflict of interest (unless resolvable by disclosure).


Accept any appointment that is contingent on the outcome of the case. Success fees and conditional fee arrangements are examples of these (any form of payment linked to the results of the Case). Conditional phrases are incompatible with the expert’s independence.


Play the role of a negotiator.

When Are Expert Witnesses Used?

When it is necessary to have opinion evidence to aid in the resolution of a dispute, an Expert Witness is required. This viewpoint may result in an early conclusion of the issue. An Expert Witness may be asked to give testimony in court and may be involved in legal procedures.

The current guidelines encourage the use of a Single Joint Expert, who is appointed by all parties to the dispute to render an opinion on the topic at hand. However, an expert witness appointed by one party is still feasible (party appointed expert). The duty of either an SJE or a PAE is the same, which is to assist the Court. Once a report is completed, the parties may raise questions about any portion of the study, and the expert is compelled to respond if the queries are for clarification. The report and any responses supplied then become part of the evidence before the court and are used to help them make a decision.