Facing Off Against a Good Expert: Challenge the opinion — don’t attack the expert!

By James Crosby

A smart, well-prepared, experienced opposing expert can be a challenge for even the most-seasoned trial attorney. The expert will go toe-to-toe with the cross-examining attorney and will not be rattled by a tough cross as may a percipient witness or a party. And an experienced, prepared expert will not fall for well-worn cross-examination tricks that some lesser experts might bite on.

If asked, “How much are you being paid for opinions here today?,” a smart, well-prepared expert will not answer, “Oh, about $40,000” to the disgust of the jury. She will answer: “I am paid by the hour for my time spent on this project and not for my opinions. My opinions are my opinions, based on the facts and my expertise, regardless of what I am paid for my time,” to the nodding admiration of a jury. Most significantly, the smart, well-prepared, experienced expert will know his or her area of expertise far better than any cross-examining attorney, no matter how much the attorney studies and prepares. Challenging a prepared expert economist on underlying economic theory or market analysis, or a computer expert on the specific of coding or chip design, can quickly become a dangerous exercise in front of a jury — nothing worse than getting shredded by the expert you are supposed to be shredding!

Given the inherent dangers of attacking the knowledge and expertise of an experienced, well-prepared expert, it is often a better approach to challenge the facts and assumptions underlying the offered opinions, or lack thereof. The opinions of any expert are only as good as the facts and assumptions upon which the opinion is based. The expert’s analysis and opinions may very well be correct and supportable based on the information and assumptions provided the expert. But if that information and those assumptions are incomplete, incorrect or shaded, the opinion may likewise be incomplete, incorrect or shaded, through no fault of the expert. So, in any case where opposing expert testimony is to be presented and subjected to cross-examination, trial counsel should consider challenging the facts supporting the opinion, as opposed to attacking the expert.

One source of effective challenge to an expert’s opinion may be an incomplete set of facts provided the expert by counsel. Experts are largely dependent on counsel and, at times, the client, to secure case-specific information upon which to work-up their opinions. Often counsel will limit the information provided to an expert. This may be done to control expert costs, because of lack of understanding of the case, by mistake or lack of time, or even, misguidedly, to shade the result or secure the opinion needed to support the case. Discovery or information provided by the client or expert may help trial counsel identify relevant facts that were not provided to the expert. In that case, the missing information can be an effective topic for cross-examination at trial. For this reason, trial counsel, in the opposing expert’s deposition, must require the expert to produce his complete file and must secure a clear and complete record of what facts and documents the expert reviewed and relied upon the offered opinion.

Often, counsel will give an expert a set of presumed facts upon which to work up and base an opinion. If that presumed set of facts is incomplete, faulty or not accurately reflective of the facts of the case, the opinion based on those presumed facts may likewise be incomplete, faulty or not accurately reflective of the facts — a source for effective topic cross-examination at trial. Again, the expert deposition is critical. If the expert based his opinion on a presumed set of facts, the expert must be required to identify such presumed facts and explain why they were relevant to the opinions provided. Then post-deposition and pre-trial, counsel, along with her expert and client, can examine such presumptions and determine whether they are suspect or incomplete and, in turn, a potential effective source of cross-examination.

The ancillary benefit of challenging the factual underpinnings and presumptions upon which an opinion is based in these or other manners, as opposed to directly attacking the credibility or expertise of the expert, is the possibility of turning the opposing expert witness into an ally at trial. Most experts will agree that his or her opinion is only as good as the information and presumptions upon which it is based.

If, on cross-examination, counsel can establish that material facts and presumptions provided by counsel and upon which the opinion is based are incomplete or incorrect, that expert may pull back from defending his own opinion. At a minimum, counsel will be able to argue at closing that the opinion is based on incorrect facts.

Granted, challenging opinions and attacking experts is largely case-specific and generally much more nuanced than the basic tenets addressed above. Particular cases can and do provide opportunities to effectively attack the credibility, expertise and even bias of an expert, even a smart, experienced, well-prepared one. However, there will be times when the opposing expert has done a fine job and reached a spot-on, fully supportable opinion, but based on incomplete facts and faulty presumptions provided by counsel. In those cases, it is always better to challenge the opinion and not attack the expert.

James Crosby is a solo practitioner.

This article originally appeared in the March/April 2017 issue of San Diego Lawyer.