Successful Daubert Motions: Best Practices for Challenging an Opponent’s Expert

Executing a Daubert challenge against an opposing party can be the deciding factor in a case.

Jared Firestone

Written by
— Updated on August 27, 2021

Successful Daubert Motions: Best Practices for Challenging an Opponent’s Expert

Due to the enormous consequences this challenge can have, it is critical for any practicing trial attorney to understand how, why, and when behind the motion. Below, we’ve broken down the process of launching a successful Daubert challenge, identifiers of the right time to deploy your challenge, and strategies to give you the greatest chance of success.

Identify When Daubert is Needed

Daubert hearings, while important, are not the only way to determine the admissibility of expert testimony. Any method of review is permitted so long as the court performs an evaluation, with a sufficient record for appellate review, and articulates the reasons for its decision. But Daubert challenges do have a place when a more thorough examination of an expert’s qualifications are needed.  If granted, a Daubert challenge guarantees that the court will extensively review the admissibility requirements of Federal Rule of Evidence 702. Under Rule 702, the court determines whether a witness is qualified to testify as an expert. This review includes assessing whether:

  1. 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
  2. The testimony is based on sufficient facts or data
  3. The testimony is the product of reliable principles and methods
  4. The expert has reliably applied the principles and methods to the facts of the case
  5. Additionally, some federal courts require a Daubert challenge if any review of an expert is to be made

Do Your Research

It’s important to thoroughly prepare before making a Daubert challenge. Begin by researching the scientific or technical issues involved in the expert’s testimony. After this, you should perform background research on the expert witness, including:

  1. The expert’s past publications
  2. Deposition and trial transcripts
  3. Licenses and certifications
  4. The record of previous Daubert challenges against them
  5. A full background check, if possible

After performing a comprehensive background review, you should retain your own expert in the field who can document the opposing expert’s errors through a deposition. Prepare a counter declaration with your own expert to show that the challenged expert’s methodology is unreliable.

Choose Your Moment

Daubert challenges can be made in many forms, including:

  1. A separate motion
  2. As part of summary judgment
  3. A motion in limine
  4. As an objection made at the time the testimony is given
  5. In a post-trial motion

Technically a challenge can be made at any point in the case, however, it is wise not to make a Daubert challenge too late in the trial. In 2001, the 10th Circuit case (Alfred v. Caterpillar, Inc, 262 F.3rd 1083, 1087) held that a Daubert challenge raised late in the trial process most likely will not be approved.

In many cases, the trial judge will issue a scheduling order that specifically includes deadlines for challenges to the admissibility of expert testimony. If a party does not comply with the order, any objections are considered waived. If a party waits to object until the time the expert testimony is actually offered, the trial court will likely refuse it for this reason as well—even if a scheduling order was absent. Thus, it is always best to challenge before the expert testimony is admitted, though not too early as to give the opposing party ample time to correct the deficiencies.

Do not hesitate to object to an expert during pre-trial if it might help to avoid a trial altogether. If a pre-trial objection fails, the moving party does not need to reassert the challenge in order to preserve it. The movant can reassert it once the evidence is actually offered. At that time, you may request a Daubert hearing if one was not previously conducted.

Consider the Scope and Content

A movant can modulate the extent of the Daubert challenge as it suits their case. In some cases, the challenge might simply involve a review of expert reports. Though in other instances, a Daubert challenge might be a lengthy proceeding involving the live testimony of the expert. If you decide that you want a full Daubert proceeding, it is important to show good cause in the motion.

As far as the content of the Daubert challenge, a movant for the challenge should focus on competence, relevance, and reliability. It is tempting to focus on the conclusions of the expert, however, judges will likely prefer to allow any conclusions to be decided at trial. Admissibility determinations can still be outcome-determinative if the expert witness was to present the only question of fact at trial. Since courts may be reluctant to exclude testimony when it could result in deciding an entire case, it is important for a challenging attorney to remind the court that the issue is simply one of admissibility. The issue is also one where the burden remains on the proponent of the evidence to prove admissibility by a preponderance of the evidence.

Account for Your Judge

Another factor in determining your challenge’s chances is to look at the history of Daubert challenges involving the judge sitting trial. Try to determine if there is a correlation between the judge granting or denying Daubert motions and the lengthiness of such motions. A judge will have the ultimate say on the extent of the Daubert challenge, though you should make a request that best suits the strengths of your case.

Regardless of the request, a judge may decide to have a full hearing or an expedited one depending on the point of the trial the motion is being made. If the expert witness testimony would create the only triable issue of fact, file the Daubert motion as part of summary judgment citing the opposing expert’s deposition and your own expert’s affidavits. Remain vigilant of the opposing expert changing their testimony. This is a sign that there was likely some flaw in the original testimony or that they are trying to bring up something that might not have survived the original objection.

Minimize the Chance of a Backfire

You should also consider whether the challenged expert might do a better job verbally stating their case than they did in their written report. A Daubert hearing could potentially become an opportunity for opposing counsel to strengthen their position. A few important questions to ask before initiating a Daubert challenge include:

  1. Did the expert leave out certain relevant qualifications that they may bring up in an oral deposition?
  2. Was their methodology poorly explained but possible to correct if the expert is given a second chance?
  3. Consider if it would be beneficial for a jury to witness a full evidentiary hearing. Will the challenging attorneys and their experts present a better case for admissibility than the challenged expert witness will on the stand?

To avoid a hearing in the presence of the jury, you can file the Daubert challenge as a separate motion or as a motion in limine—not as a part of a motion for summary judgment. You can also point to a lack of contested fact issues, or simply cost considerations, in order to support a request that the court rule without a hearing.

Defending Against Daubert Motions

You must also consider if the tables were turned—how to oppose a Daubert challenge made against your own expert witness. Remember that the proponent of the expert testimony, in this case, has to prove with a preponderance of evidence that the expert is qualified and their testimony is reliable. Therefore, it is important to keep a complete record of testimony and briefs establishing that the testimony is based on reliable methods and will assist the trier of fact.

But just an attorney’s summary explaining this is not enough. The expert must also put forth the evidence that his or her testimony meets those standards. This evidence can be presented in the following ways:

  1. Via the expert’s own deposition testimony
  2. An affidavit of the expert explaining why the methodology used is reliable
  3. References to published articles and other academic works supporting the reliability of the expert testimony
  4. Affidavits of other experts in their field
  5. Prior testimony of your opponent’s experts

You may also request extra time to provide these materials, so make time to gather all the necessary materials. Regardless, a prudent attorney should position themselves to have this evidence ready on short notice in case a challenge comes up at trial, and a request for more time is not granted.


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