Top 15 Tips for Testifying as an Expert Witness

Testifying as an expert witness is no simple task. It takes ample skill and preparation to convey knowledge in a comprehensible way to a jury. There is also substantial time and effort expended prior to trial. Below are 15 tips for expert witnesses to consider before taking the stand.

Anjelica Cappellino, J.D.

Written by
— Updated on November 2, 2022

Top 15 Tips for Testifying as an Expert Witness

1) Draft a comprehensive retainer agreement

The foundation of any solid attorney-expert witness relationship is a comprehensive retainer agreement. The retainer agreement should specify all pertinent terms and obligations of both the attorney and expert. The services to be performed, the general preparation required, and the expert’s fees should all be clearly stated in writing. If the expectations of both parties are established, they are less likely to have misunderstandings down the road.

Learn more about Expert Witness Retainer Agreements here.

2) Discuss any potential disqualification issues beforehand

Before preparation for trial commences, it is important for the expert to disclose any potential disqualification issues. An expert’s testimony may be disqualified for substantive reasons, for example, if the science behind the expert opinion is considered novel and untested. Other disqualifications may occur because of conflicts of interest, such as the expert having been previously employed by or hired as an expert for the opposing party. Because the disqualification of an expert can be detrimental to a case, it is important to discuss these issues as early on as possible.

3) Find out what your testimony will entail

While a retainer agreement should state the general subject matter at issue in the case, experts should always verify the exact nature of the testimony that the attorney is seeking. Particularly in regard to highly complex scientific matters, a greater degree of specification may be necessary so that the experts may tailor their testimony accordingly. In addition, any experiments or testing that needs to be conducted should be stated, so that the expert may be fully prepared.

4) Update your curriculum vitae

While experts will have the opportunity to establish their credentials in court, a concise, up-to-date curriculum vitae that showcases their expertise in the subject matter at issue is vital. A curriculum vitae that strongly conveys the witness’ qualifications may even result in the uncontested declaration of the witness as an expert prior to trial, saving both the time and effort of conducting a voir dire.

5) Obtain and review any and all necessary materials

In order to reach a fully formed opinion, all necessary file materials must be obtained and reviewed in a timely manner. Any materials that an expert will need should be provided by the attorney as soon as practically possible. In addition, any rules and regulations governing the dissemination of the materials should be disclosed, such as whether they are under a protective order by the court.

6) Find out if a written report is needed

In federal courts (and certain state jurisdictions), expert witnesses are required to provide a written report pursuant to Rule 26 of the Federal Rules of Civil Procedure. Under Rule 26, expert witnesses must disclose a report previewing the expert’s proposed testimony to the opposing party. The report must contain “all opinions the witness will express and the basis and reasons for them.” As such, experts should be aware of this requirement well before the due date of the report.

 7) Be careful with written communications

If the above rule is applicable, experts must be mindful of all written communications. In addition to laying out the basis of the expert’s opinion, Rule 26(a)(2)(B) of the Federal Rules of Civil Procedure also mandates disclosure of facts or data considered by the witness, any exhibits the expert intends to use, the witness’ qualifications, a list of other cases in which the witness testified, and a statement regarding the expert’s compensation for testifying. Therefore, any documents created by the expert may be discoverable.

8) Inquire about other expert witnesses

Knowing whether other experts are testifying can help narrow down the scope of the expert’s own testimony. If other experts will be handling different aspects of the subject matter, then each expert is free to focus on one specific area. Particularly in regard to highly complex or technical issues, it may be helpful that each expert concentrates on its own sub-topic, opposed to one expert flooding the jury with testimony that may overlap with the subsequent testimony of another expert.

9) Outline a case theory

The general purpose of the expert’s testimony is to clearly explain a particular issue of fact. Understanding the case theory, and how the expert’s testimony fits within that narrative, ensures that the expert will remain on track. If the one basic purpose of the testimony remains in the forefront of the expert’s mind, it is easier to craft testimony that concisely addresses the issues.

10) Prepare, prepare, prepare!

Whether an expert is experienced in testifying before a jury or not, it can still be unnerving. Also, all attorneys – including opposing counsel – have their own style, which an expert may need some time to get used to. Once the general outline of the direct examination is finished, the attorney and expert should dedicate time to reviewing the material. This can prevent mistakes from occurring inside the courtroom.

11) Practice your demeanor and non-verbal cues

In the same regard, it is vital to practice how one comes across to a jury. The actual testimony presented is only half the battle. An expert’s demeanor, posture, phrasing, tone, and other verbal and non-verbal cues are all taken into account when a jury is determining credibility. Overall, an expert should appear experienced but also likeable and trustworthy in the eyes of a jury.

12) Be prepared for a Daubert challenge

A Daubert motion, named after Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), the Supreme Court case upon which the standard for expert testimony is based, seeks to exclude the testimony of an expert witness that is not relevant or reliable. When deciding whether to admit the testimony, a judge will consider the factors outlined in Daubert. While the factors enumerated by the Daubert Court are non-exhaustive, all experts should familiarize themselves with the case, if testifying in a jurisdiction that follows that standard. A Daubert challenge is typically made before trial has commenced, and one of the first ways in which opposing counsel may disqualify the expert.

13) Be mindful of the voir dire process

A Daubert challenge is not the only time that an expert may be disqualified. The voir dire process, notably different from a Daubert challenge, centers on whether the expert is qualified to testify as to the subject matter at hand. At the beginning of the direct examination, the expert testifies to his educational background, work experience, training, and other qualifications. After this initial inquiry, opposing counsel then gets the opportunity to question the expert. Once the court rules that the witness is qualified to testify as an expert, the direct examination can continue. Opposing counsel may be able to disqualify the expert if the expert’s qualifications are weak, or if a conflict of interest exists. Therefore, an expert’s qualifications should be clearly established at the onset of the direct examination, and any conflicts of interest should be discovered well before trial.

14) A direct examination that flows

While there are many ways to conduct a successful direct examination, the main goal is to ensure that the jury better understands the facts at issue. Therefore, an expert’s testimony on direct should not just be a rote repetition of scientific terminology. The expert should use lay terms whenever possible, and explain the material by breaking it down into sub-topics or using analogies. Presentation is also important – speaking in a slow and concise manner is much easier to understand.

15) Surviving cross-examination—always remain calm

Cross examinations have a reputation for being combative. However, that does not mean that the expert should fight or struggle with opposing counsel. Sometimes, it is not what is said but how it is said that matters. Although opposing counsel may attack the expert’s direct testimony, a calm response will always trump an aggressive one. If an expert remains in control of his testimony, it is likely he may be able to sidestep or pivot a question and still maintain credibility. After all, it is the opposing counsel’s job to discredit the expert in any way possible, but how the expert handles the situation can make all the difference.

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