Lawyers must consider several factors when they choose an expert witness. The expert’s qualifications, reputation, and ability to communicate effectively are key considerations. The expert’s location and the lawyer’s budget are practical issues.
The potential for a conflict of interest is a factor that lawyers tend to forget. Fortunately, actual conflicts are rare. Experts are also challenged on the basis that she or he show a clear bias for the party that hired them. While those challenges are not usually successful, lawyers need to think about the issue of bias before retaining an expert witness.
Courts are reluctant to disqualify experts based on perceived conflicts or claims of bias. Courts tend to view those issues as going to credibility rather than admissibility.
Even if a potential conflict does not bar an expert from testifying, lawyers want to hire credible experts. Lawyers need to consider possible challenges to an expert’s credibility based on perceived conflicts or allegations of bias. Screening experts for conflicts and bias should therefore be part of the lawyer’s assessment of potential experts.
Prior Work for an Adverse Party
Courts have the power to exclude an expert’s testimony when the expert has provided services to the opposing party. Courts exercise their power to bar the testimony of an expert who has “switched sides” when they deem it necessary “to protect the integrity of the adversary process, protect privileges that otherwise may be breached, and promote public confidence in the legal system.”
Whether the expert will be disqualified generally depends on whether the expert received confidential information from the party that is relevant to the current lawsuit. A lawyer’s mental impression of the strengths and weaknesses of relevant claims against that lawyer’s client is an example of confidential information.
When there is a dispute about the expert’s receipt of confidential information, courts ask whether it was reasonable for the adverse party to believe that it had entered into a confidential relationship with the expert. If so, they examine the evidence to decide whether confidential information was actually shared with the expert.
Lawyers need to balance the risk of conflict against the reality that hiring an expert who was once retained by the opposing party may be advantageous. An expert’s willingness to work for both sides might be seen as evidence of the expert’s impartiality. Of course, it might also be seen as evidence that the expert is a “hired gun,” but that is a challenge facing every expert in every case.
When an expert has worked for the adverse party, lawyers nevertheless need to be wary. There is always a risk that the opposing party will claim that it shared confidential information with the expert. A lawyer will need to explore the expert’s relationship with the opposing party in detail and will need to assess the risk that the expert might be disqualified. If that risk is significant, the lawyer should consider whether conflict-free experts with similar qualifications are available.
The screening process should start by asking the expert whether she has any past experience with the adverse party or its lawyers. Conducting an online search for cases in which the expert testified will provide at least partial confirmation that the expert has no conflict. Still, since experts do not always testify and since it is difficult to learn of past employment as consulting experts, it is important to have a candid conversation with a potential expert witness about any contact the expert has had with an opposing party, even if the expert did not testify for that party.
Bias is often alleged by an opposing party. An expert’s consistent employment by a particular industry or group of litigants might give rise to claims of bias, but those claims are attacks on credibility that juries should resolve.
Bias may also be reflected in unreliable methodologies or a selective application of facts. Courts might disqualify experts for bias indirectly by applying the Daubert standard more strictly when there is evidence that bias may have affected the reliability of an expert’s conclusions.
Some courts have suggested that experts who base opinions on experiments or research done outside the context of litigation are more likely to produce reliable results than experts who are hired by a particular industry or group to form opinions that are specific to a lawsuit. After Daubert was remanded to the Ninth Circuit, Judge Kozinski wrote that “experts whose findings flow from existing research are less likely to have been biased toward a particular conclusion by the promise of remuneration; when an expert prepares reports and findings before being hired as a witness, that record will limit the degree to which he can tailor his testimony to serve a party’s interests.”
That line of thought suggests that courts might be more inclined to exclude experts when they have not conducted research or expressed opinions about a particular subject before they are hired to present expert testimony. Selecting an expert who has researched a scientific question outside the context of litigation might therefore avoid claims of bias.
Still, the fact that an expert has not conducted research prior to being retained does not mean that the expert’s methodology will be tainted by bias. Courts are more likely to be troubled when, for example, an expert prepares peer-reviewed writings and fails to disclose “her potential bias because of her direct involvement in litigation in the . . . cases on which she reported.”
Experts may also demonstrate bias when they prepare reports that contradict prior writings or testimony given in other cases if the contradictions cannot be explained by the differing facts that the expert considered. To screen against potential claims of bias, lawyers should always review an expert’s past writings and testimony to determine whether it might conflict with opinions the expert will be asked to express.