The role of expert witness opinion testimony is vital in litigation, though you’d probably never know it from watching a show like Suits. A potential pitfall of litigation arises when one assumes that because they’ve hired an expert, that expert’s opinions will be automatically admissible.. However, litigants must ensure that their expert’s qualifications and methodology meet the standards of the courtroom, the Daubert Standard, by applying their specialized knowledge, training, and skill in a reliable way. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). If an opponent moves to preclude or limit a litigant’s expert testimony, a failure to meet the Daubert Standard can result in the expert not getting past the gatekeeper of admissibility – the judge.
Litigants are often surprised to learn that proving liability, causation, and (especially) damages takes more than just observational or physical evidence. While specialized knowledge or experience is not required to explain to a jury which car ran the red light, the issue of whether or not the impact from the resulting accident at the speeds involved could cause certain injuries to the passengers is a different matter. To meet the burden of proof (or to cast doubt upon the proponent’s evidence), litigants need more than a lay witness’ testimony. The law permits experts in their fields to opine on such matters if their testimony will assist the trier of fact in understanding complicated theories or circumstances. However, any proposed expert must first meet the thresholds of the Daubert Standard, which has been codified in the Florida evidence code.
Under Daubert,there are two key thresholds to overcome before expert witness testimony is admissible. First, the witness must qualify as an expert by demonstrating specialized knowledge, skill, experience, training, or education. Fla. Stat. § 90.702. However, being qualified as an expert is not enough; it just moves the analysis down the line. Next, the court must analyze the methodology used to arrive at the opinions to be offered through actual testimony of the expert to see if it is sufficiently reliable. Under the Daubert standard, once qualified, an expert witness can give his or her opinions in court if:
- The testimony is based upon sufficient facts or data;
- The testimony is the product of reliable principles and methods; and
- The witness has applied the principles and methods reliably to the facts of the case.
See Fla. Stat. § 90.702; see also Daubert, 509 U.S. at 592-593.
Thus, it is important for both plaintiffs and defendants to make sure their expert will not only have the required qualifications, but that their opinions are the result of reliable analysis that will survive an opponent’s Daubert challenge. A litigant’s entire theory of the case or critical defense may never make it to jury, even if they have a qualified expert, because the expert’s opinions are not supported the right data, or enough data, or were derived from unreliable principles and methods, or the expert failed to apply those principles and methods appropriately. The court, acting as the gatekeeper, is the sole arbiter of whether an expert can testify about their opinions at trial.
Courts take their role as gatekeeper seriously. The recent opinion of the Delaware Supreme Court, In re Zantac (Ranitidine Litig.), 342 A.3d 1131 (Del. 2025) is instructive. In that case, the court held that a group of doctors and scientists failed to meet the Daubert Standard because the sufficiency and reliability of their opinions “was not established by a preponderance of the evidence.” Id. at 1151. There, the defendant challenged whether the plaintiffs’ experts reliably applied the appropriate methodologies, but the trial court “appeared to view its role as not extending to evaluating the strength of an expert’s science.” Id. at 1150. Thus, the Delaware Supreme Court reversed the decision, emphasizing that before a jury can weigh an expert’s credibility an expert must meet the Daubert Standard.
As another example, even if the expert is qualified and permitted to testify, if the law requires a certain measure of damages, failing to reliably present that evidence through an expert can mean losing the case. Earlier this year, in Bandklayder Dev., LLC v. Sabga, 406 So. 3d 265, 270 (Fla. 3d DCA 2025), reh’g denied (Feb. 4, 2025), the trial court’s award to the plaintiff was reversed on appeal because the expert for the plaintiffs used the wrong date to measure damages. Id. at 269. Rather than testify to the plaintiffs’ damages as of the date of the breach, he testified what the damages would be measured by the date of trial. Id. On appeal, the court declined to permit the plaintiffs another chance to present the damages correctly; instead, the case was remanded with instructions to enter judgment for the defendants. Id. at 270. Similarly, in Susan Fixel, Inc. v. Rosenthal & Rosenthal, Inc., 921 So. 2d 43 (Fla. 3d DCA 2006), a directed verdict was awarded in favor of the defendant after plaintiffs’ expert used the wrong date of loss when determining damages.
What these cases show is that expert witness methodology matters beyond the Daubert hearing. Even assuming the court permits the expert to testify, it is then the role of the jury to weigh the expert’s testimony context with all the facts and evidence. Thus, even if the expert’s opinions meet the minimum threshold of the Daubert Standard, the jury’s evaluation of which litigant’s expert’s qualifications and methodologies are more reliable often determines which party wins the case or the amount of damages awarded.
As the Bandklayder case demonstrates, litigants are typically afforded only one opportunity to present expert opinions, and courts will not give a do-over unless there was some judicial mistake that rises to reversible error. Bandklayder, 406 So. 3d at 270. In most circumstances, an expert witness is usually not formally trained in the law, so it is important for attorneys to first select an expert witness with the appropriate qualifications and specific experience to satisfy the first prong of the Daubert Standard. Then, the attorney must work closely with the expert to ensure that he or she has all of the information, data, context, literature, and tools required. Moreover, the expert will need sufficient time and opportunity to test, observe, analyze, and sometimes obtain peer review in order to confidently develop reliable, defensible opinions in line with the second prong of the Daubert test.
Moreover, an attorney’s deep familiarity with the evidentiary rules and case law governing expert opinions will sharpen her or his ability to identify opportunities where challenges to an opponent’s expert are necessary. In sum, the selection of an expert and ongoing ability to timely provide anything necessary to establish the expert’s reliable opinions are two of the most important responsibilities of a competent litigator.