Expert consultation

When litigating any case requiring the assistance of an expert, it is important to find the right expert as early in the case as possible. The expert will need to prepare for discovery and depositions, and can help the attorney prepare his or her discovery requests and questions for opposing witnesses. In complex cases, sometimes it is a good idea to retain an expert to act not as a witness, but as a consultant to help prepare the case, in addition to hiring an expert witness.

Consultants vs. Expert Witnesses

So what is the difference between a consulting expert and an expert witness? First, consultants do not have to be designated. One can retain the consultant for their advice and guidance and to obtain their confidentiality. These experts cannot be deposed by the opposing attorney and cannot be retained by them, either. It is not unheard of for an attorney to retain a number of well-known experts in a particular field as consultants if the client can fund for the retainers.

An expert witness, on the other hand, needs to be designated. As a witness, the expert can be subpoenaed for deposition, they may be obligated to prepare reports other discoverable materials, and so forth. While they can still perform most of the functions of a consultant, their level of confidentiality is tempered slightly by the fact that they may be compelled to provide certain information to the other side. Of course, the trade off is that an expert witness can testify at trial in front of a judge or jurors and offer their opinions directly to the finders of fact.

Crossing Over

Fortunately, an expert who is retained as a consultant is not limited to being a consultant forever. It is possible to retain an expert to consult on a case then, just prior to the deadline for announcing the expert as a witness, designate them as such. Many use this strategically as a means of limiting the other side’s access to a witness until the last possible moment and to create some doubt and confusion as to which of a number of consulting experts might eventually be called upon to testify.

Unfortunately, the process does not work in reverse as easily.  An expert witness can be withdrawn from a case, but it is rarely without ramification.  Withdrawing an expert witness can have an impact on the credibility of the case perceived by jurors in certain situations. And, why would one want to change a testifying expert to a consulting expert? The added benefit of confidentiality of an expert consultant is lost if the expert already had his or her deposition taken or reports disclosed.

Of course, although designated as a witness, it is not mandatory that a party calls a particular expert witness at trial.  Many use this strategically by naming several witnesses but only calling one or two of them in an effort to confuse the other side, and spend their precious trial preparation time allowing the other side to take potentially lengthy expert depositions of expert witnesses.


One other factor that is often overlooked: some experts might have a lower fee for consulting than for acting as a witness. The added efforts of preparing expert reports, making time available to testify at trial and in depositions, and the other considerations that go along with actually serving as a witness justify charging a higher rate and spending more hours on a case. A consultant, on the other hand, can be just as useful for preparing for trial, short of testifying, but because there is less of a commitment, they might be less expensive overall.


While there are pros and cons to each approach, it is important to understand not only the obvious differences between a consultant and an expert witness, but also the strategic advantages of each approach. Of course, while it is possible to use designation strategically in various ways when switching between consultant and witness status, a final matter to be considered is the preference and experience of the expert. If the expert does not wish to testify or feels that they would serve the client’s interests best in a consulting role, this must be considered. Similarly, if an expert witness does not have a great deal of experience testifying, but is objectively brilliant in every other way, it may be wise to use him or her as a consultant and to put a more experienced witness on the stand.

By: Christopher Eri, Esq.