photo of male hand pointing to draft expert witness report on table

Documentation and Disclosure of Expert Witness Draft Opinions and Reports

  • February 21, 2023
  • Dr. Yasser Korany and Wade Morris

It is not uncommon for a forensic investigator who has been retained as an expert witness to consult one of their peers on the matter under investigation, particularly if a range of theories seems to be possible. It is also encouraged, and has recently become a typical practice, that expert witnesses forward their draft reports to one of their internal or external peers for review. Sometimes, the fact that the report has been reviewed is mentioned in the body of the report; other times there is no indication as to whether the report has been reviewed by others. When mentioned, there is typically no information on the extent of any changes that may have been made because of the review process.

There remains a lack of clarity around record keeping and disclosure requirements for expert witness consultations and draft reports and whether it is appropriate for expert witnesses to send their reports to their peers for technical reviews. The question here is: When a draft report has been reviewed by one of the expert witness’s peers, what is the impact on the independence of the expert’s opinion and what are the requirements for documentation and disclosure? With this article, we help to answer this question.

Types of Report Reviews

The reviews of expert witness reports can be classified as editorial or technical. Editorial reviews aim to improve the readability of a manuscript and address obvious errors or omissions. The reviewer examines the manuscript for ways in which it can be clarified and simplified, and suggests adding or rearranging material, reordering paragraphs, or restructuring sentences. Editorial reviews may also include proof-reading tasks such as identifying typos, misspelled words, and grammatical errors. In Ontario, editorial reviews of expert reports are permitted. Technical reviews may be carried out by supervisors or peers internal or external to the authors’ organization.

The term peer review is used to signify that the technical review was carried out by an external professional and not a co-worker. Technical reviews involve a review of findings for plausibility and the consideration of all relevant observations. Technical reviews have the advantage of identifying unintended bias and inconsistencies between the facts of the case and the findings. Professional Engineers Ontario Guideline titled Professional Engineers Reviewing Work Prepared by Another Professional Engineer defines technical review as “a review of a document to determine whether the engineering content of the work is correct, complete or suitable for the intended application1.” 

Traditionally, a peer-review is the process of independent technical critique by an external reviewer who is not affiliated with the author. As such, a review by a colleague within the same organization would be best described as a technical review and not a peer-review. One can think of the peer-review process as a non-adversarial scrutiny of the authors’ assumptions, methods, and conclusions aimed at helping the authors address any real or perceived gaps in their analyses. In these kinds of situations, the question may sometimes arise whether the technical or peer-review may affect the independence of the expert.

The Doctrine of Independence

The 1993 decision in the infamous Ikarian Reefer case established that the expert witness report is expected to be, and is required to be seen to be, the independent and uninfluenced product of the expert that is free, in terms of form and content, from any pressures arising from the litigation process2.

Independence refers to the independence of the expert from the party seeking to tender the expert evidence and goes beyond the fact that experts are retained and paid by litigants and not the court3. The January 2010 amendments to the Rules of Civil Procedure4 addressed the form and content of expert reports to clarify for experts the rules for maintaining independence. Soon after those amendments, the Ontario Superior Court of Justice in the case of Ikea Properties Ltd. v. 6038212 Canada Inc5 confirmed that the amendments to the Rules of Civil Procedure relating to experts require expert witnesses to provide a fair, objective and non-partisan opinion.

Expert witnesses have a duty of neutrality and impartiality and are required to provide opinions that are their own and only within their areas of expertise. They are also reminded by the Rules of Civil Procedure that they are not advocates for the clients and that their primary duty is to the court.

Pre-Discovery Disclosure  

The case of Ikea Properties Ltd. and other recent case law have signalled that any information that was relied upon by the expert in formulating their professional opinions may be required to be disclosed. In that case, the court explained that “relied on” means the information was used to support or exclude an opinion.

The issue of disclosure by an expert witness in the regulatory context was tackled by the Ontario Court of Justice in the Norton decision which was released in 20076. The court clarified that while it is not unreasonable for expert witnesses to seek review of their reports, the reviewers must be identified, and the experts must state any changes to their opinions based on the suggestions provided by the reviewers. Because the expert in the Norton case did not disclose the fact that the report was peer-reviewed and that four separate drafts of the report were generated, the court did not admit the expert witness’s evidence.

Whereas litigation privilege can exempt lawyer-expert communication from having to be disclosed as held in the Moore v. Getahun 2015 decision of the Ontario Court of Appeal7, litigation privilege does not necessarily extend to the technical/peer reviews of the expert witness draft opinions and reports. It should be noted that the Norton decision originated in the regulatory context, and Moore originated in a civil context. There are different interests at stake in each. Nevertheless, an expert would be prudent in either context to be conscious of how technical or peer reviews may be perceived to affect independence.


Before finalizing their reports, experts are often asked to discuss their findings and conclusions with the client’s lawyer to ensure that the report is clear, easy to understand by the non-expert, and covers all the issues of the case. This practice is harmless provided that the experts maintain objectivity and are not pressured, or otherwise unduly influenced, to alter their professional opinions in support of the client’s position.

A review of draft reports for technical accuracy and completeness prior to the issuance of the final report is not only an acceptable practice but also recommended by several professional bodies such as the Forensic Practices Committee of the American Society of Civil Engineers8. However, the professional opinions and conclusions must remain those of the expert authoring the report.

The Rules of Civil Procedure do not prohibit experts from sharing draft opinions with their clients, clients’ counsel, or their peers. However, any changes to the original opinions must be documented in the final report and the draft report that has been revised must be preserved for potential requests for pre-discovery disclosures particularly when the experts revise their opinions as a result of the technical review. Changes that are editorial in nature do not require documentation or disclosure.

It is indeed a breach to the standard of care and an ethical misconduct when experts stray from the duty of objectivity and impartiality to advocate on behalf of the clients’ cause or attempt to colour the truth to help the client’s case.


  1. Professional Engineers Ontario [2011]. Professional Engineers Reviewing Work Prepared by Another Professional Engineer.
  2. National Justice Compania Naviera Sa v. Prudential Assurance Co Ltd. [1993].  2 Lloyd's Rep 68 "THE IKARIAN REEFER" Queen’s Bench Division (Commercial Court).
  3. Solomon Friedman [2014]. Expert Independence, Bias & Impartiality: A Matter for Admission or Weight. 26th Annual Criminal Law Conference. CanLIIDocs 33366, retrieved on Jan 1st, 2023.
  4. R.R.O. 1990, reg. 194, r. 53.03.
  5. Ikea Properties Ltd. v. 6038212 Canada Inc., [2010] O.J. No. 3449. (S.C.J.).
  6. R. v. Norton, [2007] O.J. No. 811 (O.C.J.).
  7. Moore v. Getahun, [2015] ONCA 55 (CanLII), retrieved on Jan 11, 2023.
  8. ASCE Forensic Practices Committee [2012]. Guidelines for Forensic Engineering Practice. American Society of Civil Engineers.

About the authors

photo of co-author Dr. Yasser KoranyDr. Yasser Korany is a construction litigation expert and the Principal of KSI Engineering, a firm that specializes in investigating structural collapses and building envelope failures. He has been qualified numerous times as an expert witness by all levels of the court in both Canada and USA. He is a board-certified senior member of the National Academy of Forensic Engineers and the Founding Chair of the Forensic Engineering Technical Committee of the Canadian Society for Civil Engineering.

photo of co-author Wade Morris


Wade Morris is the principal of Wade Morris Litigation Counsel Professional Corporation and has been practising civil litigation since 2007. His practice areas include commercial, estates, and property-related litigation. He was admitted to the Law Society of Upper Canada in 2007 and has made numerous successful appearances before the Ontario Superior Court of Justice.