Communicating with Experts

June 19, 2014 | Riccardo Del Vecchio

As evidenced by the recent case of Moore v. Getahun, the scope of permissible interactions between counsel and expert witnesses is a recurring issue that arises from time to time when experts are called to testify at trial. The Advocates’ Society has recently developed and approved a set of “best practices” that litigators should consider following in their interactions with experts. I will briefly summarize them, though a full review of the principles.

Given a duty to present reliable, clear, comprehensible and relevant expert evidence, an advocate can (and should in many cases) have an appropriate degree of consultation with testifying experts, including appropriate input into the format and content of an expert’s report or affidavit before it is finalized and delivered. What is to be avoided is any communication likely to interfere with the expert’s duties of independence and objectivity, which would result in a disservice to the expert, the client and the court.

The advocate’s duty when engaging an expert is to inform the expert of his or her role in the process and of the nature and content of the expert’s duties, including the requirements of independence and objectivity. Since there is a possibility that the expert’s file will be disclosed, the advocate should advise the expert of same and counsel the witness not to destroy relevant records.

Further, the advocate must ensure that the expert witness receives all relevant information and documentation concerning the matters at issue and understands the issue on which the expert has been asked to opine. The lawyer should advise the expert that this receipt of information and documentation is subject to applicable rules of confidentiality.

The expert witnesses must understand they are able to probe and question information and assumptions provided to them before completion of their analysis and/or expression of their opinions. An advocate should discourage an expert from preparing a draft report until the expert has a proper understanding of:

  • the issue to opine on;
  • the facts and assumptions upon which the opinion will be based;
  • the documentation and information relevant to the opinion sought (irrespective of whether same is helpful or harmful to the case); and
  • the need to confine his or he ranalysis, observation and opinion to matters that lie within the expert’s expertise.

This will assist the advocate in her/his obligation to take reasonable steps to protect a testifying witness from unnecessary criticism.

A determination as to the appropriate degree of consultation with a testifying expert and the appropriate degree of the advocate’s involvement in preparation of an expert’s report or affidavit will depend on several factors as well, including the nature and complexity of the case in question, the level of experience of the expert, the nature of the witness’s expertise, and other relevant circumstances of the case.

In appropriate cases, an advocate should also consider entering into an agreement with opposing counsel relating to matters such as agreed limits on disclosure of draft reports and communications with experts, and limits on demands for production of the files of experts


This blog sets out a variety of materials relating to the law to be used for educational and non-commercial purposes only; the author(s) of this blog do not intend the blog to be a source of legal advice. Please retain and seek the advice of a lawyer and use your own good judgement before choosing to act on any information included in the blog. If you choose to rely on the materials, you do so entirely at your own risk.