Expert Witness Report:

Question: What are the key requirements for an expert witness report to be admissible in an Ontario court case?

Answer: In Ontario litigation, courts generally assess expert evidence using the admissibility framework from R. v. Mohan, 1994 CanLII 80 (SCC), focusing on relevance, necessity, no exclusionary rule, and proper qualifications, with judges also weighing benefits versus risks as described in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23.   Alfred Legal Services provides Affordable Legal Help for Ontario clients by explaining what your report should include, how to reference supporting documents clearly, and common issues that can lead to exclusion.

Understanding the Requirements When Preparing an Expert Witness Report Document for Court Litigation Purposes

A proper, well crafted, expert witness report can make the difference between success or failure within a lawsuit; and accordingly, avoiding mistakes within an expert report is of utmost importance so to ensure that the expert report is admissible, and may be relied upon, within the court proceeding. If an expert report is deemed inadmissible, such may jeopardize the legal case.

The Law

Admissibility

When reviewing whether to admit an expert report as evidence, a court will seek to ensure that the report meets the required admissibility criteria.  Expert evidence admissibility criteria summarized within 2599475 Ontario Inc. v 2549445 Ontario Inc., 2023 ONSC 3508, whereas it was stated:

Quality Expert Reports

Communicate Clearly and Effectively

Prior to drafting a report, the expert should review the required scope of the report with the representative, being the lawyer or paralegal, who seeks the report.  Depending on the nature of the court case, the report may require broad details or may require a narrow focus.  In some circumstances, a brief report is adequate; and in other circumstances a more lengthy report is necessary.  Forgoing this review can result in the waste of preparing an insufficient report or the waste of preparing an excessive report.  Either is a waste of time and therefore money.

A proper expert report includes, and properly references, the evidence documents that support the expert opinions and conclusions.  The evidence documents can, and should, include pictures, study data, testing results, among other details, all provided as attached appendices or schedules.  A bibliography referencing any authoritative documents or studies that are used to support opinions and conclusions should also be included.

An expert report should express opinions clearly and concisely while being easy to read in an organized and professional layout with spelling, grammar, and punctuation, carefully reviewed for correctness.  The expert report should be written with a vernacular and tone that is consistent with the language of the intended audience whereas, for example, differences may be required for legal cases heard by a judge versus legal cases heard by a jury; and accordingly, language should remain within the understanding of the average layperson while avoiding belittlement of judges, lawyers, and other experts.  Reports should be careful to limit the use of industry specific jargon or abbreviations known only to those with expertise within the relevant field; and, where industry jargon or abbreviations are necessary, a reference table or key to provide definitions should be provided within the report.

More Hints

• Use professional letterhead;
• Use a cover page as well as an index or table of contents;
• Use a curriculum vitae or resume to summarize the qualifications and credentials that confirm that the expert is genuinely an expert;
• Use an introduction page to outline when, and from whom, the report was requested;
• Use 12-point font and double spacing;
• Use headings;
• Use short, concise paragraphs;
• Use a unique reference number for each page, table, chart, and appendix;
• Use a definitions page or section to define technical language and industry specific jargon or abbreviations; and
• Use an upfront summary page to outline final conclusions or opinions.

Things to Avoid

An expert report must be impartial and objective.  The role of an expert is to provide an unbiased opinion to the court for the purpose of aiding in the truth-seeking mission of the court.  The expert must therefore ensure that the expressed opinion is grounded in facts and evidence rather than prepared with a favouring of a litigant.

• Avoid absolute wording and phrasing;
• Avoid words that appear as hedging or guessing;
• Avoid critical commentary regarding credibility of other experts;
• Avoid a scientific and clinical tone by keeping the tone friendly and personable;
• Avoid going into details beyond the purpose of the report;
• Avoid unnecessary adjectives or superlatives.

Summary Comment

The expert preparing an opinion report must remain attentive to the balance required when obtaining input from a legal representative whereas the lawyer or paralegal seeking the report will best understand the factual concerns and legal issues that relate to why the report is needed and can explain the desired scope; however, the findings and opinions as stated within the report must always remain the genuine unslanted view of the expert as author of the report.