I prepare expert reports in the knowledge that an opponent will likely move to exclude my opinions, and I have seen each of those motions fail. The Daubert challenge is a motion asking the court to exclude an expert opinion(s) before a jury is permitted to hear it. Surviving a Daubert challenge is, in my considered view, a valuable event in the professional life of an expert witness. It is a credential to be disclosed rather than an escape to be forgotten.
The Value of Surviving a Daubert Challenge
Consider what actually occurs when a challenge fails. The opposing party has scrutinized the methodology supporting an opinion, retained its own experts to expose weaknesses and rebut, and asked a judge to declare the opinion unreliable and withhold it from the jury. The judge has examined the method under that adversarial process and declined to exclude it. Little else in professional life creates a test of that kind. Peer review is generous by comparison, for it is a collegial exercise that does not set out to dismantle the work.
This validation acquired greater force in December 2023, when Rule 702 was amended. For years, many courts had admitted testimony of (arguably) doubtful reliability and left the parties to contest it before the jury. In my (non-legal) opinion, the amendment generally foreclosed that practice. The proponent of an expert must now demonstrate that the opinion is reliable and that the opinion must reflect a sound methodology applied properly to the facts, among other requirements. To satisfy that standard today is a more demanding achievement than it was a few years ago.
Survival also produces a durable record. A ruling that admits an opinion is a written finding by the court. When the expert’s same method is offered in a later matter, that finding could stand as evidence of reliability and bolster future admissions. Such records accumulate, and each favorable ruling should make the next challenge more difficult to sustain.
Philosophically Speaking…
There is a deeper principle at work, the one Nietzsche captured in the title above. Stress that fails to break a thing may instead strengthen it. Nassim Taleb gave the idea a modern name, “antifragility,” the property of systems that improve under pressure rather than merely enduring it. The expert who has defended a method line by line, under hostile examination and judicial scrutiny, becomes antifragile. Subsequent cross-examinations hold fewer surprises, because the method has already withstood the most rigorous form of the attack. Judges and juries read that composure as credibility, and credibility is a currency in which expert testimony is valued.
The asymmetry deserves emphasis. An expert who is never challenged can be considered lukewarm. An expert who is challenged and excluded suffers a genuine loss. An expert who is challenged and prevails has converted an assault into an asset, so that the very motion intended to end the engagement becomes strength on the record.
Why Experts Should Disclose the Record to Prospective Clients
Here many experts hesitate, and they are mistaken in doing so. Retaining counsel confronts a familiar problem at the outset of any engagement. They require an expert whose opinion will withstand challenge, yet they cannot readily assess that quality in advance. In the language of information economics, they face an asymmetry: the reliability of an expert is largely hidden from the party who seeks it. A record of surviving Daubert challenges is a strong signal available to them, precisely because it has already been tested by a court.
It follows that an expert should disclose that history plainly and early. It belongs in early conversations with counsel, without boasting about it. To name a record of survival is to furnish counsel with important data and to let them weigh the risk of a challenge before they are committed. The expert who has prevailed against such motions and remains silent withholds information of real value from the very people deciding whether to place their confidence in the work.
Disclosure carries a second advantage. It signals to the opposing party that the success of future challenges are unlikely.
A Warning to Opposing Litigators
A Daubert motion can be a costly undertaking. It consumes attorney hours and frequently requires a competing expert, and a motion that fails may cost credibility with the court. A prudent adversary weighs that cost against the probability of success. Where the intended target has survived such challenges before, the probability of success falls, and the cost of the attempt rises. Weak motions are then left unfiled, and stronger ones are pursued with greater caution. The settlement value of the case may adjust accordingly. A proven expert does more than win the motion; the reputation of that expert discourages the motion from being filed at all. A disclosed record of survival may thus operate as a form of quiet deterrence.
The Mechanics of the Daubert Challenge
As most older attorneys know well, for most of the twentieth century, admissibility turned on Frye v. United States (1923): expert opinions were admissible only if they had attained general acceptance in its field. The Supreme Court displaced that standard in the federal courts in Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993), which cast the trial judge as gatekeeper under Rule 702 of the Federal Rules of Evidence and directed attention to whether the methodology behind an opinion was reliable. Later decisions completed the framework. See General Electric Co. v. Joiner (1997) and Kumho Tire Co. v. Carmichael (1999). (That last holding is why the badge is available to an engineer, an economist, an accountant, or a compliance professional as readily as to a scientist.)
The forum is significant. Federal courts apply Daubert and Rule 702. A clear majority of states have adopted Daubert or a close variant, while a minority retain Frye or a hybrid of the two. Arbitration proceeds on a different footing, since the Federal Rules of Evidence do not bind an arbitral tribunal. Even so, arbitrators continue to assess reliability, and counsel continue to frame their objections in Daubert terms because those terms persuade.
A Necessary Qualification
Not every exclusion marks a deficient expert. Testimony is sometimes excluded because a field is genuinely novel, a deposition is unclear or moves in an unforeseeable direction, or a ruling may reach only one among several opinions the expert advanced. And of course an expert who has never faced a Daubert challenge is not necessarily weak on that account. The worth of surviving a Daubert challenge lies in the tenacity, the quality, and the facts and circumstances of each expert’s work individually.
Conclusion
The heat of the forge does not flatter the metal; it tests it, and what emerges is harder than what was placed within. A Daubert challenge is a test of that kind, and the opinion that survives it is uniquely validated. Nietzsche stated the principle in a single sentence more than a century ago, and it applies with unusual precision to this area of the expert profession. What does not exclude the expert makes the expert stronger. The expert who has passed through carries the result as a mark of standing, and should say as much to hiring litigators.
