What Goes Into a Properly Prepared Expert Report?

An Expert Witness Report Should Follow Style, Format, and Content, As Proper For a Court Proceeding. A Legal Representative Can Assist and Guide the Expert With the Proper Crafting; However, the Legal Representative Must Refrain From Influencing the Views and Opinions Expressed Within the Expert Report.

Understanding the Requirements When Preparing An Expert Witness Report Document For Court Litigation Purposes

Expert Witness Report Involves a Well Documented and Supported Opinion From a Subject Matter Expert Various best practice habits when preparing expert reports can help ensure a well-crafted document that is both effective and efficient for use within the courtroom. Indeed, a quality expert report can be the difference in making or breaking a case; and accordingly, the choice of expert, the style of report, and the manner used when expressing expert opinion, require careful review.

The Law

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:

[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.

It is also necessary that the supporting evidence documents reviewed by the expert are adequately included and properly referenced.  The expert opinion contained within a report should, and perhaps must, refer to supporting evidence documents such as pictures or testing results, among other things, attached as appendices or schedules.  Additionally, a bibliography to summarize any authoritative documents used for research should 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.

Need Help?Let's Get Started Today

ATTENTION: Do not send any confidential information through this web form.  Use this web form only to make an introduction.

Send a Message Directly to KLP Paralegal Services

ATTENTION: Confidential details about your case must not be sent through this website.  Use of this website does not establish a legal-representative/client relationship.  Do not include confidential details about your case by email or phone.  Use this website only for an introduction with KLP Paralegal Services. 
Privacy Policy & Cookies | Terms of Use Your IP Address is:
KLP Paralegal Services
Professional Corporation

Unit 600, The East Mall, PO 11577
Toronto, Ontario,
M9B 4B1

P: (416) 570-6378
F: (905) 629-8630
E: klp@klparalegal.com


9:00AM – 5:00PM
9:00AM – 5:00PM
9:00AM – 5:00PM
9:00AM – 5:00PM
9:00AM – 5:00PM

By appointment only.  Call for details.
Messages may be left anytime.

Sign Up