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2020 Keep Seminar Part I: Judges Share Insight on Expert Witnesses

Updated: Feb 22, 2021

On September 17, 2020, the San Diego Chapter and the Southern District of California held Part I of the Sixteenth Annual Judith N. Keep Federal Civil Practice Seminar. The Keep Seminar honors Judge Judith Nelson Keep, who was the Southern District’s first female judge and first female chief judge. With 550 participants, the seminar began with a tribute to Judge Keep from Judge William Enright, who passed away earlier this year. In the first of two panels, Chief Judge Larry A. Burns, Judge Dana M. Sabraw, and Judge Anthony J. Battaglia shared their insight on expert witnesses in federal court. The written materials for this panel can be found here.

Judge Battaglia – Basics of Expert Testimony and Discovery

Speaking first, Judge Battaglia covered the basics of expert testimony and the pretrial discovery obligations concerning experts. He shared that one common mistake attorneys make is cherry-picking the information that is provided to their experts. This cherry-picking leads to expert opinions that are not based on sufficient facts and data, which are then subject to exclusion. Attorneys should instead make sure their experts have access to all the information necessary to consider everything relevant to their field of testimony.

Judge Battaglia shared that another common pitfall involves litigants’ duty to supplement their expert disclosures. This duty requires timely disclosure when litigants learn that part of their expert disclosures is incorrect, such as when an expert changes an opinion provided in an expert report. Judge Battaglia emphasized that “timely” disclosure means when litigants learn something is incomplete or incorrect, not when they eventually make their final pretrial disclosures. If a disclosure is untimely, Judge Battaglia cautioned that courts will determine the consequences by examining factors that include the litigant’s due diligence and the opposing party’s ability to address the surprise change in expert testimony.

Judge Sabraw – Using Expert Witnesses at Trial

Next, Judge Sabraw shared his advice on admitting expert testimony and managing experts at trial. In addressing Daubert motions that seek to exclude expert testimony, Judge Sabraw expressed that the success of these motions varies based on the type of expert being challenged. A Daubert motion is well-suited for challenging an expert who testifies based on scientific knowledge. A Daubert motion is unlikely to succeed, however, in challenging an experience-based expert, such as a mechanic. Judge Sabraw explained that this distinction is due to the higher hurdle for science-based testimony, which often can be challenged with peer-reviewed literature and scientific testing. He also advised that Daubert motions rarely succeed when they are used to challenge experts’ qualifications.

As for managing experts at trial, Judge Sabraw recommended that attorneys view experts from the jurors’ perspective. Jurors are distrustful of experts and often view them as paid advocates. Therefore, Judge Sabraw suggests attorneys spend less time asking experts about their qualifications and lofty credentials. Instead, attorneys should focus on the important facts that experts can speak to that will put jurors in the best position to decide the issues based on their understanding of the case. Further, Judge Sabraw shared that jurors do not like being told ultimate conclusions by an expert regarding specific conduct in the case. Rather, Judge Sabraw recommended that attorneys ask experts hypothetical questions that use assumed facts. This approach allows jurors to apply the hypotheticals to their understanding of the case and make a decision for themselves.

Chief Judge Burns – Cross-Examination of Experts

Finally, Chief Judge Burns focused on the cross-examination of experts. He advised attorneys to not swing for the fences, but instead try to accomplish one of the goals of cross-examination. These goals include: (1) impeaching the expert through damaging testimony; (2) extracting testimony from the expert that is favorable to the cross-examiner’s side of the case; and (3) pitting the expert against another adverse expert by revealing disagreements between the experts.

Further, Judge Burns shared that it is a mistake for attorneys to try to elicit every possible impeaching fact on cross-examination. Instead, attorneys should set self-imposed limits and consider trying to make only three telling points on cross-examination. And when determining what points should make the cut, attorneys should weigh the strength of impeachment evidence by considering how recent the information is, how strongly the information is connected to the witness, and how directly the information relates to the witness’s credibility. Judge Burns also recommended that attorneys: (1) ask plainly worded, short questions, (2) avoid value-laden words that let the expert express contrary opinions, and (3) avoid argumentative questions that simply quarrel with an inference being drawn from the evidence.


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