Vetting experts in an adversarial system

Antitrust disputes often raise complicated issues of law, economics, and facts, which go to the heart of the matter. Successful resolution of these issues usually requires the help of experts or specialists in the field. Use of such authorities is permissible because of Federal Rule of Evidence 702, which states in part: “[i]f scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify thereto in the form of an opinion or otherwise.”

Under Fed. R. Civ. P. 26(a)(2)(B), disclosure of an expert witnesses “must be accompanied by a written report[1] – prepared and signed by the witness.” Failure to do so may result in the exclusion of an expert’s testimony “unless the failure was substantially justified or is harmless.” Fed. R. Civ. P. 37(c)(1). As a result, in antitrust cases, courts often face hundreds of pages of expert reports on key issues. Two tools that judges have available to them are concurrent expert evidence proceedings and economics day or tutorials.

Concurrent expert evidence

Courts have many tools at their disposal to evaluate the views of experts. In addition to the traditional tool of Daubert motions, courts have used Concurrent Expert Evidence (CEE). CEE is the practice whereby two or more experts at a hearing give their evidence concurrently, thus permitting simultaneous questioning and discussion on the key issues. The experts’ testimony may take the form of opening reports followed by a dialogue either between the experts themselves, or by their answering questions mediated and managed by the judge. This replaces the typical question and answer format between an expert witness and his or her lawyer. While lawyers are not excluded from the process, they do not play the same predominant role as questioner in chief. Rather, lawyers may ask questions only as the judge allows. The CEE technique certainly diminishes the direct control of the lawyer and enhances the flexibility and extemporaneity of the expert(s).

While CEE is not specifically dealt with in the Federal Rules of Civil Procedure or Federal Rules of Evidence, the Federal Rules of Evidence do provide a framework for the CEE technique. First, Rule 104 states that trial courts “must decide any preliminary questions about whether a witness is qualified,” and “[i]n so deciding, the court is not bound by evidence rules, except those on privilege.” Fed. R. Evid. 104(a). The Advisory Committee Notes also state that “[t]o the extent these inquiries are factual, the judge acts as a trier of fact.” Second, Rule 611, although ostensibly focused on trial proceedings, gives trial courts “reasonable control over the mode and order of examining witnesses and presenting evidence so as to," among other things, “make those procedures effective for determining the truth” and "avoid wasting time.” Fed. R. Evid. 611(a)(1)-(2). The Advisory Committee Notes explain that this rule empowers trial courts to decide "whether testimony shall be in the form of a free narrative or responses to specific questions," "the order of calling witnesses and presenting evidence," and "the many other questions arising during the course of a trial.” Third, Rule 614, while also focused on trial, authorizes trial courts to “call a witness on its own . . . .” Fed. R. Evid. 614(a). The Advisory Committee Notes explain that “the authority of the judge to call witnesses” and “to question witnesses” is “well established.” The advisory committee notes caution against judges “abandon[ing] [their] proper role and assum[ing] that of advocate.” They also state that “the manner in which interrogation should be conducted and the proper extent of its exercise are not susceptible of formulation in a rule.”

Given the issues confronting courts in antitrust cases, it is not surprising that many judges have utilized CEE. For example, in In Capacitors Antitrust Litigation, Judge Donato used CEE with the following characteristics:

  • The experts were required to submit a joint statement that listed the top 10-12 issues of disagreement by descending order of importance;
  • Experts were the drafters of the joint statement, not the lawyers;
  • The Court used the joint statement as an agenda for the discussion;
  • The witnesses were invited to comment on each other’s remarks, and to pose questions;
  • Counsel for the parties sponsoring the witnesses may be allowed to ask follow-up questions at the Court’s discretion;
  • At the end of the proceeding, the Court asked each witness to summarize his or her position on selected issues, and to identify issues for which disagreement has been resolved;
  • The witnesses will be put under oath; and
  • The discussion will be reported.

In re Capacitors Antitrust Litigation, MDL Case No. 17-md-02801-JD, ECF No. 82.

Judge Donato used CEE again In re Google Play Store Antitrust Litig., No. 21-md-02981-JD, 2022 U.S. Dist. LEXIS 213670 (N.D. Cal. Nov. 28, 2022), where he denied Google’s motion to exclude Plaintiffs’ economics expert testimony under Fed. R. Evid. 702 after adopting the CEE approach (putting the opposing experts head to head to parse out the critical differences in their analyses).

Judge Zouhary used CEE in In re Polyurethane Foam Antitrust Litigation.  See In Re Polyurethane Foam Antitrust Litigation, No. 1:10-md-02196, ECF. No. 967. He used CEE because “I felt I needed to see them and to question them directly. This would not be a traditional hearing for counsel to wax on, but a focused hearing with direct contact between me and the experts.” [2]  He went on to demonstrate the value of CEE, noting, “It was great to have the experts in the courtroom at the same time, nearly face-to-face, with questions they could not duck, and to have the opposing expert comment on what he or she had just heard.” Judge Zouhary found the experience “rewarding and will not hesitate to utilize it again in the right case. What is ‘the right case?’ One that involves multiple experts and a lengthy record, or perhaps a complex Markman hearing.” Id.

CEE does indeed have many benefits. From the hundreds of pages of expert reports, it efficiently narrows the parties on the most important disputes. It also allows for direct communication with the experts that is not subject to spin or filters. This is because the conversational nature allows experts to better express their opinions, rather than simply answering a lawyer’s questions. Importantly, it is a chance for the judge to have all of his or her questions answered by the people who know. It also encourages the experts to find common ground, with an obvious benefit to the court and the jury. Two experts in the same industry, talking to each other, are more likely to agree on principles and reasoned arguments, as their credibility relies upon it.

Economics day or tutorials

Another method used to vet experts can be in the form of tutorials. While not used as a formal vetting mechanism due to their nature, tutorials can help courts cut through and/or master mountains of economic and factual evidence. In In re Blue Cross Blue Shield Antitrust Litigation, Judge Proctor utilized two staggered days to require the parties to present complex economic and factual elements of the case. Also known as Economics Days, those sessions were to “provide the court with an overview of the economic issues associated with the case in an objective format and without advocacy.” See In Re Blue Cross Blue Shield Antitrust Litigation, Case No. 2:13-cv-20000, ECF No. 906. The parties agreed to certain ground rules:

  • Presentations were off the record without a court reporter and were not to be publicly disclosed, used, or admissible for any purpose in the litigation;
  • Attendance was limited;
  • No counsel or any other person was permitted to utilize any form of recording during the proceedings;
  • Witnesses were selected by counsel and could include subject matter experts as well as testifying experts; and
  • Written submissions helpful to the Court were submitted in advance.

The format was lecture-style presentations that incorporated the use of demonstrative visual aids. Parties were also allowed to lead the experts through a modified direct format to focus the lecture presentation. The court was permitted to ask questions of any witness or counsel, and the court could consider requests from counsel or the parties to pose certain questions to a party, participant, counsel or expert.

In antitrust cases, Economics Day has many advantages. First, it provides the court with an overview of the economic issues associated with the case in an objective format. It also allows the parties to frame the issues that they think will inform future decisions by the Court, including discovery issues that the court may face. The court may be better informed to make discovery decisions once it has a better understanding of the economic issues that will be at issue in the case. For example, knowing that the profits of a certain company will be key to plaintiffs’ theory of the case may make decisions about discovery of financial data easier to decide. Having the tutorial off the record permits the parties to present evidence at an early stage in litigation without fear of having to pivot later once the record is more developed. Since it cannot be cited, there is no prejudice to the parties.


CEE and Economics Day should each be seen as part of the continuum for evaluating experts’ role in antitrust cases as well as mastering complex legal and economic foundations of antitrust cases.  They are just additional tools available to assist courts in evaluating experts, which includes preparing reports, depositions, trial testimony and cross-examination.

*Megan Jones is Co-Chair of Hausfeld’s Antitrust Practice Group and Partner in San Francisco.


[1] Whether experts wrote their own report can be a litigated issue. See Holley v. Gilead Sciences, Inc., Case 4:18-cv-06972, ECF No. 1198 at 5 (“the Court concludes that neither the four nephrologist experts nor the four infectious disease experts ‘prepared’ their reports”).
[2] “Jumping In — A Different Approach to Expert Evidence,”

Other Publications