February 26, 2020 Articles

Give the Jury the Tools to Decide: Expert Testimony under Rule 702

Expert testimony consisting of little more than reciting evidence and reaching a conclusion risks usurping the jury’s role.

By Mark J. Schirmer

Rule 702 of the Federal Rules of Evidence allows parties to introduce expert testimony to aid the jury in fact-finding. See Fed. R. Evid. 702(a). Given this license, parties seek to use experts for a variety of purposes, including explaining technical or economic concepts, demonstrating adherence to technical standards in design, explaining causation (or the lack of it), and establishing injury and damages.


In jury trials, the jury’s job is finding facts. It is the contention here that expert testimony consisting of little more than reciting evidence and reaching a conclusion risks usurping the jury’s role—or at the very least, making the jury’s job much harder. Thus, for the most part, courts should discourage, and advocates should hesitate to present, expert testimony that constitutes little more than fact-finding or drawing conclusions without explanation of the standards that underlie that opinion. Admittedly, the line between testimony that does little more than find facts and draw factual conclusions, as opposed to testimony that applies technical or expert know-how to a set of facts, is often unclear. Thus, unless advocates and judges discourage raw opinion testimony, juries can face situations where they must choose between competing experts and explanations without a clear basis for making that choice—other than a subjective reaction to witnesses.

The courts appear to allow two basic approaches to expert testimony regarding culpability (whether the conduct alleged was consistent with legal requirements) and damages (whether the conduct alleged caused cognizable monetary losses). One approach involves examining the expert qualifications and whether the basis for expert opinions has a reasonable grounding in the relevant science, technical area, or other area of expertise, allowing expert opinion regarding the factual issues at hand.

The other approach is for the expert to identify objective standards or benchmarks for evaluating the evidence and then explain to the jury how the evidence, as the expert understands it, fits the benchmark. This approach to expert testimony provides an objective—or at least subject-matter tested—“control” for evaluating the evidence or for comparing what is with what should be or should have been. See Fed. Judicial Ctr., Reference Manual on Scientific Evidence 218, 220, 222 (3d ed. 2011) (an adequate control or benchmark is needed to allow a comparison to draw inferences about issues such as causation and the effect of the actions at issue); J.T. Colby & Co., Inc. v. Apple Inc., 2013 U.S. Dist. LEXIS 65959, at *22–23 (S.D.N.Y. May 8, 2013) (to reliably put a value on the test variable, analyses must employ adequate controls), aff’d, 586 F. App’x 8 (2d Cir. 2014). In employing this approach, one of the expert’s jobs is to find and explain a proper benchmark or control, one that will allow the expert’s analysis—and thus the jury’s fact-finding—to filter out irrelevant factors and focus on the one or ones that are relevant to the issue at hand. In damages analysis, for example, the courts describe this as finding an “untainted” benchmark period (a control or comparison period that has as little of the challenged conduct as possible). See In re Urethane Antitrust Litig., 166 F. Supp. 3d 501, 502–3 (D.N.J. 2016); Fed. Hous. Fin. Agency v. Nomura Holding Am., Inc., 2015 U.S. Dist. LEXIS 16034, at *5 (S.D.N.Y. Feb 10, 2015) (noting the need for an untainted control or benchmark).


Of course, simply identifying the relevant control or standards does not make an expert’s testimony admissible. Before experts can testify as to their conclusions—conclusions that a jury may evaluate—experts should link their conclusions to the evidence and explain how the relevant standards or benchmarks apply to the evidence. Otherwise, expert explanations and opinions may constitute little more than an expert’s unsupported or free-form musings regarding the meaning of the evidence. See Schulenberg v. BNSF Ry. Co., 911 F.3d 1276, 1283–85 (10th Cir. 2018) (affirming exclusion of expert testimony where the expert did not explain the links between the standards identified and the application of those standards to the evidence); Hendrix ex rel. G.P. v. Evenflo Co., Inc., 609 F.3d 1183, 1197–1201 (11th Cir. 2010) (excluding expert testimony that failed to provide sufficient basis for the purported links between theory and the expert’s conclusions in the context of the evidence and facts of the case).

There are several benefits of having experts, where possible, explain the standards or objective benchmarks for examining the evidence. First, it helps avoid situations where the conclusions that the expert reaches and the lawyer urges the jury to adopt come largely from the expert’s say-so, or ipse dixit. See Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997) (“[N]othing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert. A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered.”); Daubert v. Merrell Dow Pharm., Inc., 43 F.3d 1311, 1316–19 (9th Cir. 1995) (admissible expert testimony should be more than merely experts’ statements that they are correct); Bona Fide Conglomerate, Inc. v. SourceAmerca, 2019 U.S. Dist. LEXIS 50949, at *7 (S.D. Cal. Mar. 26, 2019) (finding it was incumbent on the court to exclude testimony based only on expert say-so).

Second, the benchmark approach helps avoid making the result a pure likability contest between experts. Jurors do not like having experts simply “tell” them what to do. They will disregard experts they find arrogant. By focusing expert testimony to provide a guide for the jury such that jurors draw their own conclusions, rather than have experts draw conclusions for the jury, advocates and courts facilitate decisions on the merits. See Walker v. Spina, 2019 U.S. Dist. LEXIS 4018, at *13 n.13 (D.N.M. Jan. 9, 2019) (discussing juror reactions to experts).

Third, providing jurors with the relevant benchmark or standards and having experts explain their view of the application of those standards to the facts allows the jury to function more directly as the fact finder, testing the evidence for itself rather than merely accepting an expert’s view about the meaning of the evidence presented. It empowers the jury, rather than diminishes the jury’s role. See United States v. Stapleton, 2013 U.S. Dist. LEXIS 160442, at *4 (E.D. Ky. Nov. 8, 2013) (noting that allowing certain expert testimony “empowered” the jury to evaluate the evidence).

Stated in jurisprudential terms, having experts provide the jury with the applicable standards or benchmarks and explain how those standards relate to the facts facilitates Rule 702’s underlying purpose—to aid the jury in making the decision. See Fed. R. Evid. 702 (“A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if: (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue. . . .”); Daubert, 509 U.S. at 591 (expert testimony is admissible only if it assists the trier of fact in resolving material, factual disputes). And by aiding the jury in making its own decision, it avoids replacing the jury’s evaluation of the evidence admitted and presented in the courtroom with expert “opinion,” which can rest, in part, on factors and information inadmissible in court. See Fed. R. Evid. 703 (“An expert may base an opinion on facts or data in the case that the expert has been made aware of or personally observed. If experts in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject, they need not be admissible for the opinion to be admitted.”); United States v. Leonard, 738 F. App’x 7, 9 (2d Cir. 2018) (expert opinion should not invade jury’s role as fact finder); United States v. Diaz, 876 F.3d 1194, 1197 (9th Cir. 2017) (same); see also In re Methyl Tertiary Butyl Ether (MTBE) Prods. Liab. Litig., 725 F.3d 65, 114 (2d Cir. 2013) (“The role of an expert is not to displace the jury but rather to ‘provid[e] the groundwork . . . to enable the jury to make its own informed determination.’” (quoting United States v. Duncan, 42 F.3d 97, 101 (2d Cir. 1994)).


Whenever possible, courts and advocates should strive to have experts do more than simply apply accepted methodologies to a set of facts and opine as to the meaning of those facts in light of relevant standards in professional or academic fields. To help and empower juries in fulfilling their role in trials, advocates and experts should, whenever possible, provide juries with the relevant standards for evaluating the evidence the juries will hear and that the experts will evaluate so that the juries can evaluate the facts, not merely accept experts’ factual findings based on which experts juries find more likable.

Mark J. Schirmer is a partner with Straus & Boies, LLP, and a former senior trial attorney for the U.S. Commodity Futures Trading Commission.

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