Exposing Expert Witness' Bias During Cross: Collateral Attack

, New York Law Journal


Ben Rubinowitz
Ben Rubinowitz

When preparing for a cross-examination, the skilled litigator must always first determine his "theory" of the cross: Specifically, it must determine if the suggestion to the jury is that the witness is truthful, honest but mistaken, or purposely exaggerating or shading his testimony to help one particular party. Where the theory of the cross-examination is that the witness is intentionally attempting to mislead the jury, then exposing the reason for the witness' deception, i.e., his bias, is a crucial goal of the cross-examiner. Asking questions which allow the jury to see that the witness is not as credible as he or she would have the jury believe is a key component of this type of attack. But when dealing with the expert witness, exposing bias is not only an essential part of cross, but one that becomes imperative if counsel is to turn the jury against the so-called "expert."

To expose such bias, one of the most effective methods is to focus on matters collateral to the central issue(s) in the case. This cross-examination technique, known as the collateral attack, can be one of the most effective methods to discredit the expert. At its core, exposing bias through the use of the collateral attack is one of the greatest and most time-tested techniques available to counsel. It goes without saying that the bias, hostility, or motives of an expert witness are relevant and proper subjects for impeachment.

The witness' financial bias often serves as the basis for the collateral attack. But to make the cross-examination on collateral matters even stronger, there are other avenues of attack that should be explored before focusing solely on financial interests. While many of these avenues will eventually lead back to financial bias, and are indeed intertwined with the expert's own financial interests, these lines of questioning often provide independent fodder for a compelling cross-examination.

To develop a strong collateral attack, research is essential. The Internet has become one of the most valuable tools for gathering information about experts. Not only are publications posted on the Internet, but disciplinary actions against the expert, resumes or curricula vitae, price lists, websites and jury verdict reporters, among other things, are posted there as well. In preparing to conduct a collateral attack of an expert, counsel must dig deep. Clearly, the more information counsel has for attacking the witness, the better the cross-examination will be. The focus of such fact-gathering prior to trial is to determine whether the expert witness has some personal or financial incentive to provide a particular opinion at trial.

Oftentimes, the "regular" or "assembly-line" expert will purposefully inflate his or her credentials to try to impress the jury. If the attorney has not done his or her homework, that expert will likely carry the day in court. If, however, the attorney is thoroughly prepared, and is able to expose exaggeration on the part of the expert regarding his credentials, not only will that expert's credibility quickly fade, but the attorney who called that witness to the stand will likely lose credibility with the jury as well.

Set-Up and Attack

Imagine the scenario in which an accident reconstructionist is called to the stand as an expert witness. Not only does this witness hold himself out as an expert in the field of accident reconstruction, but he also testifies that he has expertise on medically related issues. He offers opinion evidence on liability and causation, opining that the subject injuries were not caused by the impact, but were preexisting injuries. Prior to the cross-examination, counsel did his homework and is well prepared for the collateral cross.

While counsel could conduct a voir dire examination, prior to the time the so-called expert offers his opinion on causation, the better approach might be to wait for the opportunity to conduct a full-blown cross. Clearly, this is a strategy call. A voir dire examination is a mini-cross for the court designed to expose the expert's lack of qualifications on the area about which he intends to offer opinion testimony. If counsel is victorious on voir dire, the result is that the court will not allow the expert to offer such testimony. Strategically, counsel might be better off allowing the witness to testify regarding his questionable opinion evidence, and then exposing the witness as one who is less than credible on cross. To do this effectively, counsel must take his time in setting up the witness for the fall.

Q: Sir, you have offered your opinions to the jury as an accident reconstructionist, true?

Q: You base those opinions on many things, correct?

Q: Based, in part, on your review of the physical evidence, correct?

Q: Based, in part, on your review of the deposition testimony?

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