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Expert Witness Report: A Well Documented and Supported Opinion from a Subject Matter Expert
Question: What are the key requirements for an expert witness report to be admissible in court?
Answer: An expert witness report must satisfy the criteria set out in R. v. Mohan, 1994 CanLII 80 (SCC), which includes relevance, necessity in assisting the trier of fact, the absence of any exclusionary rule, and a properly qualified expert. Reports should communicate clearly, include appropriately referenced supporting documents, and maintain professionalism while being accessible to laypersons. Adhering to these guidelines enhances the likelihood of report admissibility and success in legal proceedings. For assistance with expert reports, consider reaching out to United Legal Services for professional support.
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
For a court to admit an expert report as evidence the expert report must meet the criteria of admissibility. The criteria was summarized within the case of 2599475 Ontario Inc. v 2549445 Ontario Inc., 2023 ONSC 3508, where it was said:
[35] The test for the admissibility of expert evidence is based on the criteria set out in R. v. Mohan, 1994 CanLII 80 (SCC), 1994 SCC 80, as follows:
a) Relevance;
b) Necessity in assisting the trier of fact;
c) The absence of any exclusionary rule, apart from the opinion rule itself; and
d) A properly qualified expert.
[36] In White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, [2015] 2 S.C.R. 182, the Supreme Court divided the admissibility requirement into two distinct steps. First, a trial judge considers the four Mohan criteria. Then the judge balances the potential risks and benefits of admitting the expert evidence.
Quality Expert Reports
Communicate Clearly and Effectively
Before starting to craft an expert report, the expert is wise to carefully review the purpose and needs which the report is to serve by discussing such with the lawyer or paralegal who are seeking 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. Failing to conduct this review may result in the expert wasting the effort of preparing an excessively detailed report or useless preparing an insufficient report; and whereas both possibilities may result in a waste of time, such is also a waste of 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.
The report should read clearly with ease and appear professional and proofed for proper spelling, grammar, and punctuation. The expert should write in a style directed towards the intended audience, balancing need that the report be understood by an average layperson without belittling highly intelligent judges and lawyers or other experts. Reports should omit or limit industry specific jargon and abbreviations; but, if such is necessary, include definitions 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
A biased or slanted expert report can be disastrous – and should be! The expert is expected to provide opinion as a friend of the court for the primary purpose of assisting the court in the truth finding effort. The expert, while having an opinion that may favour one litigant over another, must base the opinion on authentic reasons rather than as friend 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.