The Science Behind Expert Disqualification: A Guide

Confidential Relationship

As a threshold issue, a party must show that it reasonably believed a confidential relationship existed with the expert it is seeking to disqualify. Historically, many courts followed a bright-line rule that once the expert is retained and receives confidential information, he or she is disqualified from serving as an adverse expert. However, some courts have become more flexible to account for public policy concerns such as “expert shopping,” i.e., that parties may attempt to strategically disqualify experts that could give harmful testimony against them. Courts now commonly require that the relationship between the expert and the attorney be more than a mere consultation. Lynne Bernabei et al., “Ethical Duties and Standards in Disqualifying, Retaining, and Communicating with Expert Witnesses,” 43 Brief 1 (2013). Courts will consider the following factors in making this determination:

• whether there was a formal confidentiality agreement
• whether the attorney provided the expert with documents
• whether the expert was retained
• how many times the expert and attorney met
• whether the expert was paid
• whether the expert formed any opinions regarding the case

Confidential Information

A confidential relationship by itself is not sufficient to disqualify an expert; the party seeking disqualification must also show that the expert received confidential information. These two tests are not altogether separate—the court considers many of the same factors in determining whether the information was sufficiently confidential as it considers when determining whether there was a confidential relationship. In addition, courts may also consider the following:

• whether the information was specifically related to the litigation at hand
• whether the information was privileged
• whether the information would have been discoverable regardless of the expert’s relationship with the party seeking disqualification
• whether the information was purely technical

Fundamental Fairness and Resulting Prejudice

When the two-part test doesn’t yield a strong result, courts will consider public policy—focusing on fundamental fairness and resulting prejudice. The following are some of the more common considerations:

• whether a party appears to be “expert shopping”
• the availability of a replacement expert
• the party’s ability to gain access to any specialized knowledge possessed by that expert through other means
• the burden of replacing the expert
• the right of experts to “pursue their professional calling”
• the appearance of impropriety
• any other prejudice that will result from disqualification (or the lack thereof)

Common Cases

The two most common situations where a party seeks to disqualify an expert based on a conflict of interest are (1) when an expert switches sides in the middle of an ongoing dispute and (2) when an expert was previously retained by the adverse party. When an expert switches sides in an ongoing litigation, the analysis is straightforward. However, when the expert testified for the adverse party in a different litigation, or when there is a more tangential connection, the analysis is more subjective. Courts still employ the two-part analysis in these situations, but they will also consider the degree of overlap between the content of the litigations and the expert testimony.

Typically, experts are disqualified based on their involvement in a different litigation when the expert received confidential information that is specifically related to the matters about which the expert is expected to testify—an overlap of parties or general subject matter is not sufficient. The Northern District of Illinois illustrated this principle in Bone Care International, LLC v. Pentech Pharmaceuticals, Inc., in which it allowed experts to testify both for and against the same defendant in contemporaneous patent litigations. 2009 WL 249386, at *2–3 (N.D. Ill. Feb. 2, 2009). In Bone Care, the experts’ testimony related only to the distinct patents at issue in each litigation and not to the overall case strategy. The court relied on the lack of overlap in the patent testimony to hold that the experts never received information “specifically related” to the litigation in which they would be adverse to the defendant.

However, if a party seeks to admit an expert previously employed by the adverse party in an analogous action, courts tend to find that the information is specifically related and disqualify the expert. For example, the court in In re Diet Drugs Products Liability Litigation addressed a toxic tort litigation by Cynthia Righetti against Wyeth, Inc., in which Righetti’s proposed expert had been previously retained by Wyeth to testify about the same diet drugs against a different plaintiff. No. 07-20144, 2009 WL 1886131 (E.D. Pa. 2009). The court easily found sufficient overlap to disqualify the expert, pointing to ample evidence that the expert was informed of confidential case strategies, drug information, and other confidential material “specifically related” to the drugs involved in the litigation at hand.

In sum, while disqualifying an expert due to a conflict of interest is not a precise science, courts are guided by the principle that experts should be disqualified when they have received relevant confidential information from an adverse party as a result of a confidential relationship. When that principle yields an ambiguous result, they turn to public policy considerations. The analysis described above is the federal common-law doctrine that has developed through applications of this principle, with the courts keeping an eye on fundamental fairness and resulting prejudice.

Keywords: litigation, expert witnesses, conflict of interest, disqualification

Brian Hooven is an associate with Proskauer Rose LLP in New York City, New York. 

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