United States: Cross-Examination Of Plaintiff’s Expert: The Art Of War

Co-written by Edward E Rundell

If the courtroom is the battleground for the hearts and minds of the jury, cross-examination of the opposing expert is the minefield. Through years of experience every litigator accumulates an arsenal of weapons designed to defuse the potentially explosive testimony presented by the expert witness.

Any student of trial techniques knows of Irving Younger’s "Ten Commandments of Cross-Examination." While Younger’s commandments were intended for cross-examination of witnesses generally, defense disciples consider the commandments a mantra for the cross-examination of plaintiff’s expert witness.

Before applying Younger’s Commandments to the cross-examination of plaintiff’s expert, however, defense counsel must prepare thoroughly and consider carefully the substance of the examination.

The general who wins a battle makes many calculations in his temple before the battle is fought. The general who loses a battle makes but few calculations beforehand. Thus do many calculations lead to victory, and few calculations to defeat; how much more no calculation at all! It is by attention to this point that I can foresee who is likely to win or lose.¹

Application of Younger’s Ten Commandments to the cross-examination of plaintiff’s expert requires thorough knowledge of (1) the expert, (2) the subject matter, and (3) the theory of the case.

Effective cross-examination depends, in part, on defense counsel’s knowledge of the expert’s educational background, work experience, publications, and courtroom experience. Defense counsel should conduct a data base search for every case in which the expert has appeared. These cases may yield information which can be used to limit or discredit the expert’s testimony.

Defense counsel should also consult witness banks or industry groups for cases in which the expert has testified and the names of counsel who have cross-examined the expert. Depositions and trial transcripts from other cases will allow counsel to borrow the most effective cross-examination techniques to use against the witness.

Another valuable source of background information is defense counsel’s own expert. Experts often find themselves opposing familiar colleagues in litigation. In addition to providing background information, the defense expert may offer insight into personality traits which render the opposing expert vulnerable on cross-examination.

Valuable information about plaintiff’s expert can be gleaned from materials published by the expert. Defense counsel should gather and study every work authored by the expert which bears any relevance to the issues of the case at hand.

Defense counsel will ordinarily receive a copy of the opposing expert’s curriculum vitae in response to targeted discovery or by local court rule. The curriculum vitae may list licenses or memberships held by the expert in professional and honorary organizations. Counsel may discover that an expert’s license has lapsed or has been revoked, events that deserve mention on cross-examination. And, a laundry list of honorary organizations may lose its luster when it is disclosed that membership is attained by application only, with minimal threshold requirements. Thus, defense counsel should contact licensing agencies and honorary organizations to discover the expert’s current membership status.

There is no substitute for a thorough deposition in preparing for cross-examination of plaintiff’s expert. The deposition provides the groundwork for cross-examination at trial, especially if counsel intends to obey Younger’s commandment to "know the answer before the question is asked."

If information favorable for the defense is to be obtained from plaintiff’s expert, it is most likely to be obtained at the deposition, rather than at trial. Plaintiff’s expert is more likely to affirm the qualifications of defendant’s expert, to identify areas of agreement with that expert and to criticize plaintiff’s conduct in a deposition than in a courtroom. Once committed to a position in the deposition which turns out to be harmful to plaintiff’s case, the expert faces one of two options, each favorable for defendant: he will maintain the position established at the deposition or he will change his testimony and suffer the embarrassment of impeachment.

While an expert need not master "the law" to be an effective witness, the litigator must become an "expert," of sorts, in the witness’ area of specialty to conduct an effective cross-examination.Before the deposition, and certainly before trial, defense counsel must thoroughly review published materials on the substance of the expert’s testimony. The expert’s report must be studied, researched, and critiqued. Defense counsel must confer with an expert who will continue the education process to the point of exhaustion. Mastery of the subject matter is imperative for, when cross-examining an the expert witness, "a little knowledge is a dangerous thing."

Every case must have a theory, an explanation of "how" and "why," which lies at the heart of the dispute. Defense counsel must fully understand the theory of plaintiff’s case. This knowledge is critical to effective cross-examination of plaintiff’s expert. Defense counsel should cross-examine plaintiff’s expert with the goal of (a) undermining plaintiff’s theory and (b) supporting the defense theory.

Armed with a thorough knowledge of the expert, mastery of the subject matter, and an understanding of the theory of the case, counsel is prepared to cross-examine the opposing expert. The substance of the cross-examination is drawn from the state of mind, perception, knowledge, and opinions of the expert.

While "state of mind" inquiries have nothing to do with the subject matter of the litigation they may convince the jury that the expert’s testimony is unworthy of belief. These seemingly extraneous matters may speak volumes about the expert’s credibility. The goal of "state of mind" cross-examination is to paint the expert as an advocate rather than an impartial commentator on the issues.

Many experts are frequently engaged by a certain attorneys. Cross-examination of these experts must explore the details of their relationship with the attorney, including the number of cases, the frequency of association, and the fees generated by the relationship. Cross-examination regarding substantial fees alone is not as potent as it once was. If the cases are numerous, the assignments frequent, and the fees large, defense counsel may effectively argue in summation that the expert’s testimony is unworthy of belief because of the expert’s obvious bias. No juror expects an expert to bite the hand that feeds him. Some experts come to testify only for plaintiffs, while others testify only for defendants. If defense counsel has identified this positional bias during the investigation of the expert’s background, that bias must be exploited on cross-examination.

Finally, every experienced litigator has encountered the "professional expert," whose opinions are determined not by the merits, but by the litigant who arrives first. Some apply their expertise to everything from ice-makers to pacemakers. Others specialize in automotive components, trigger locks, or clothes dryers. Although the approach will differ for the "generalist" and the "specialist," the fact that the expert does little more than testify or prepare to testify may lead the jury to question his credibility.

While some resources consider "perception" a part of the expert’s "knowledge," there are compelling reasons to give this aspect of expert cross-examination its own space. Presumably, every witness is called to testify to facts or opinions based on what the witness has perceived. In some trials, however, the expert may not have "perceived" first hand evidence which is critical to his analysis. In personal injury cases, for example, the neurosurgeon who removed the disc and performed the fusion may have "perceived" more than the physician who saw plaintiff for an independent medical evaluation. The accident reconstruction expert who visited the scene or inspected the vehicles for crush and impact damage may have "perceived" more than the expert who relied only on photographs. An expert’s advantage of having personally perceived facts relevant to the determination of a material issue must be exploited on cross-examination.

The expert witness may be cross-examined on his general knowledge, to the extent that it is relevant to his opinions, and on his knowledge of the specific facts of the case. The former examination is designed more to challenge the witness’ expertise, while the latter examination challenges the soundness of the expert’s opinions.

The time for examining the expert’s general knowledge depends on the goal of the examination. If the goal is to demonstrate the expert’s lack of knowledge and thereby disqualify him or limit the scope of his expertise, the opportunity must be taken when the expert is offered for voir dire. If, however, it is apparent that the expert will survive an objection to his expertise, cross-examination on the expert’s knowledge should be deferred until the expert is tendered for cross-examination on the merits.

Defense counsel should never miss the opportunity to cross-examine plaintiff’s expert on his knowledge of specific, relevant facts. In personal injury litigation, for example, a treating physician may have no knowledge of plaintiff’s prior medical history of accidents or injuries which relate to the issue of causation. A demonstration of the expert’s lack of knowledge of relevant facts makes for compelling cross-examination.

The expert witness is unique because he is allowed to offer opinions which, if persuasive, determine the result at trial. Therefore, defense counsel must challenge those opinions and demonstrate the unreliability of the expert’s conclusions.

One approach is to reveal inconsistencies between the expert’s present opinions and those expressed by the expert in the past. Even if the variance is slight, the impact on the jury’s assessment of credibility may prove significant.

Defense counsel may also demonstrate that the expert’s opinion conflicts with the substance of a learned treatise. The effect of such cross-examination is enhanced if the expert is the author of or a contributor to the treatise (a situation not uncommon in medical malpractice cases involving so-called "big name" experts).

Inconsistencies may also be exploited when plaintiff’s counsel makes what frequently turns out to be the mistake of hiring two experts on the same topic. War stories about experts on the same side who have reached different conclusions, or the same conclusion for different reasons are all too common. In such cases, defense counsel has the rare opportunity to impeach each expert with the conflicting opinions of the other.

The opinions offered by plaintiff’s expert are presumably based on facts or on assumptions which, in turn, have some bases in facts. On cross-examination, defense counsel may change the assumptions and vary the facts on which the expert’s opinion is based with the goal of getting plaintiff’s expert to agree with defendant’s position. The success of such cross-examination correlates directly with the degree to which the defense assumptions or factual variations are deemed reasonable by the jury.

The exigencies of time and space do not allow elaboration on each of Younger’s Commandments as they relate to cross-examination of plaintiff’s expert, but several merit at least brief comment.

After plaintiff’s counsel has walked the expert through his credentials, his fees, his protocol, his assumptions, his understanding of the facts and his opinions, defense counsel can benefit from the contrast by limiting cross-examination to one, two, at most three impeachment themes.

Skilled plaintiff’s counsel will have the expert articulate his opinion in the parlance of the masses. If she does not, defense counsel has the opportunity to interpret testimony for the jury in a manner favorable for the defense. The "automotive vehicle" is "the car," "state your name for the record" is "tell us your name," "state your date of birth" becomes "when were you born?" For maximum impact, cross-examination should be couched in language that the jury understands.

The key to cross-examination of experts, even more so than with lay witnesses, is control. Leading questions offer that control.

Discovery makes obedience to this commandment possible. Nothing is more satisfying than impeachment of an expert who changes his deposition testimony at trial.

Don’t ask plaintiff’s expert to concede the ultimate point. Elicit the facts, the assumptions, and the bases for the expert’s opinions. Then, dissect them for the jury in closing argument when you are in total control.

While this article has focused on principles of cross-examination of plaintiff’s expert in a civil trial, these principles have broader application to cross-examination of practically any expert in almost any setting.

This article is hardly an exhaustive treatment of expert cross-examination. There are countless resources available for the trial lawyer interested in honing his or her cross-examination skills. Some are included in the reading list below.

Cross-examination of plaintiff’s expert represents only one of many skirmishes played out in the course of a trial. The defense counsel who obeys the "ten commandments," and uses his knowledge of the expert, the subject matter, and the theory of the case to attack the expert’s state of mind, perception, knowledge and opinions, greatly increases his chances of navigating the minefield and capturing the hearts and minds of the jury.

1The passages at the beginning of each major section are taken from, The Art of War by Sun Tzu (J. Clavell ed. 1983).