Become an expert witness

Becoming an expert witness in U.S. federal courts can be challenging, exciting, nerve-wracking and fulfilling. But before you make plans, first study the rules and history contained in the U.S. Daubert standard.

If you decide to become an expert witness, you won’t be in court as an advocate but as a professional explaining complex facts to the judge and jury in clear, plain language. You might spend months before the trial analyzing records, writing an expert report, meeting with attorneys, and preparing exhibits like charts, timelines and damage calculations. On the day of your testimony, you’ll take the stand under oath to present your methods, findings and conclusions in a credible, neutral way.

However, if you live in the U.S., you must first understand and meet the rules in the Daubert standard to qualify as an expert witness in federal cases.

Determining admissibility of expert witness testimony

In 1993, the U.S. Supreme Court established these rules determining the admissibility of expert witness testimony in federal courts, following its decision in Daubert, et. al v. Merrell Dow Pharmaceuticals, Inc.

The case arose when the parents of two children sued Merrell Dow Pharmaceuticals, claiming that the drug Bendectin caused their children’s serious birth defects. Merrell Dow had submitted expert testimony based on published studies showing no causal link between Bendectin and birth defects. The plaintiffs also presented expert testimony that cited newer, unpublished re-analysis and animal studies that suggested a link between the drug and birth defects.

Previously, a trial court had granted summary judgment for Merrell Dow, ruling that the plaintiffs’ expert evidence didn’t meet the “general acceptance” standard established in Frye v. United States (1923), which was the prevailing test for expert witnesses at the time. Under Frye, scientific evidence was admissible only if it was generally accepted in the relevant scientific community.

On appeal, the Supreme Court rejected the Frye standard for federal courts, applying the version of Federal Rules of Evidence 702 that was applicable in 1993. The court held that Rule 702 hadn’t incorporated the Frye test and imposed a flexible gatekeeping role on judges to ensure expert testimony was relevant and reliable. The Federal Rules of Evidence Rule 702 was amended at the end of 2023 to align with the Daubert rules. 

Summary witnesses (or fact witnesses) may only attest to what they’ve seen, and aren’t allowed to give their opinions. They may also be excluded from the rest of the trial so that they’re not tainted by others’ testimonies.

Expert witnesses, however, are often key participants in trials because they can explain to judges and juries the intricacies of trials’ forensic accounting, economic damages and business valuations, which often involve complex financial transactions, accounting principles and auditing standards.

A prosecutor may call upon you to testify as an expert witness, with possible compensation, or a client involved in civil litigation might hire you to testify about your fraud examination findings.

Evolution of the Daubert standard

The “Daubert Trilogy” of cases have shaped how courts handle expert testimony:

Case 1: Daubert et al v. Merrell Dow Pharmaceuticals, Inc. (1993)

The U.S. Supreme Court established a five-point test to determine an expert witness's qualifications.

1. Testability: A scientific theory or technique must be capable of being tested or falsified through observation and experimentation: The method must make predictions that can be confirmed or disproven. Courts look for whether the theory has been tested and whether the testing supports its conclusions.
2. Peer review and publication: Have other experts in the field subjected the method or theory to scrutiny through peer review or publication in reputable scientific journals? Peer review doesn’t guarantee reliability but suggests that the work has met some minimum standards of scientific scrutiny. An expert who bases their opinion on unpublished, unreviewed work may face a credibility challenge.
3. Error rates: Does the method have a known or potential error rate, and has that rate been quantified? This factor considers the accuracy or precision of the method and if the error rate is acceptable for its intended use. The reliability of a method is suspect if the expert relies on a technique with a high or unknown error rate.
4. Standards and guidelines ensuring uniform application: Do established protocols, standards or controls that govern how a technique must be applied exist? These reduce the risk of subjective or inconsistent results when different experts use the same method. An expert should follow these recognized guidelines or best practices.
5. General acceptance: Do experts in the relevant scientific community accept the method or theory? This was the sole test under Frye but is now just one factor under Daubert. An expert who uses fringe or novel theories must show strong evidence that their approach is reliable.

Case 2: General Electric Co. v. Joiner (1997)

This case allowed appellate courts to review if a trial court misused its discretion in admitting expert testimony, thereby increasing oversight. The Supreme Court addressed how much deference appellate courts should give to trial judges when they exclude expert testimony under the Daubert standard. 

The case arose when Robert Joiner, an electrician, sued General Electric and other companies, claiming that his exposure to polychlorinated biphenyls (PCBs) caused his lung cancer. The district court excluded the testimony of his expert witnesses and ruled that the experts’ conclusions were based on studies that were too dissimilar to Joiner’s situation and involved leaps in logic. Evidence had shown that Joiner had smoked for eight years, and his family had a history of lung cancer related to persistent smoking.

The Supreme Court upheld the trial court’s exclusion, clarifying that appellate courts should apply an “abuse of discretion” standard when reviewing a trial judge’s decision to admit or exclude expert testimony. (“Abuse of discretion,” according to the Merriam-Webster Legal Dictionary is “an error of judgment by a trial court in making a ruling that is clearly unreasonable, erroneous, or arbitrary and not justified by the facts or the law applicable in the case.”) This decision reinforced the trial judge’s role as a gatekeeper under Daubert, which gave them broad discretion to determine if the scientific evidence was reliable and relevant.

Case 3: Kumho Tire Co. v. Carmichael (1999)

The Supreme Court in this case clarified that the Daubert standard for assessing the reliability and relevance of expert testimony applies not only to scientific experts but also to technical and other specialized knowledge. A tire on a vehicle driven by Patrick Carmichael blew out, and the vehicle overturned. One passenger died and the others were injured. The Carmichael family alleged the tire was defective and sued its manufacturer, Kumho Tire. The plaintiffs’ expert, a tire failure analyst, claimed the blowout resulted from a manufacturing defect, but the district court excluded his testimony, finding his methodology unreliable under the Daubert standard.

The Supreme Court unanimously upheld the exclusion and held that trial judges must serve as gatekeepers for all forms of expert testimony, whether it’s scientific, technical or otherwise. The court emphasized that the Daubert factors are flexible and may be tailored to fit the nature of the expertise in question. Kumho Tire broadened Daubert’s reach and ensured that courts critically evaluate the reliability of any expert’s methods and reasoning — regardless of the field of expertise.

Rule 702 revised in 2023

Effective Dec. 1, 2023, the revised Rule 702 of the Federal Rules of Evidence emphasizes the reliability and relevance of expert testimony. Experts qualified by knowledge, skill, experience, training or education may testify if it’s more likely than not that:

• Their specialized knowledge will assist in understanding the evidence or determining a fact in issue.
• Their testimony is based on sufficient facts or data.
• Their testimony results from reliable principles and methods.
• Their opinion reflects a reliable application of the principles and methods to the case facts.

How fraud examiners become expert witnesses

Relevant qualifications and experience

Qualified fraud examiners must have substantial training and experience in forensic accounting, fraud investigation, internal controls or related financial analysis.

Many hold credentials such as Certified Fraud Examiner (CFE), Certified Public Accountant (CPA), Certified in Financial Forensics (CFF) or other specialized forensic certifications.

They often develop expertise through years of practical work on fraud cases, financial statement analysis, asset tracing, embezzlement investigations and litigation support.

Engagement by counsel

Attorneys hire fraud examiners when they need experts to analyze complex financial records and explain findings in plain language to courts. Before a trial, a fraud examiner may submit a written report detailing their methods, findings and opinions.

Qualification under rules of evidence

Fraud examiners eligible to be expert witnesses must show they have the requisite knowledge, skills, experience, training and education to understand the evidence. Their testimonies are based on facts and data, and result from reliable principles and methods. Their opinions reflect reliable applications of those principles and methods. 

Best practices for becoming an effective expert witness

Stay within your expertise. Testify only about topics you’re qualified to speak on. Never overstate your knowledge.

Use reliable, well-documented methods. Base opinions on accepted forensic accounting practices, recognized standards, and data that can be tested and verified.

Be objective and impartial. Your role is to assist the court, not to advocate for one side. Be clear, fair and credible.

Communicate clearly. Use plain language when explaining technical details. Avoid jargon and speak confidently but simply.

Prepare thoroughly. Review all relevant documents, prepare exhibits that clearly illustrate your findings and rehearse your testimony. Anticipate cross-examination questions that may challenge your methods, assumptions or bias.

Demonstrate your qualifications. Be ready to testify about your education, certifications, years of experience, publications, speaking engagements and prior expert witness work.

Maintain credibility. Disclose any limitations in your analysis or potential weaknesses.

How you prove your expertise

• Résumé/CV: Your detailed curriculum vitae highlights education, certifications and case experience.
• Expert report: A clear, thorough report that shows your analysis follows accepted standards.
• Direct testimony: Confidently explain your background, methods and conclusions in court.
• Be prepared to defend your methods under cross-examination by showing they meet the Daubert rules.

Use your skills and experience in a new way

Expert witnessing can be fulfilling. You’ll be using your hard-earned skills to explain and clarify complicated evidence and procedures to judges, juries and the gallery. But before you begin your journey, study the rules in the U.S. Daubert standard to learn the history of expert witnessing and the mandatory qualifications.

Marcie Jones, CFE, is the executive director of Follow the Funds LLC. Contact her at MRJ@FollowTheFundsLLC.com.

Expert witnessing engages the mind and the central nervous system

Expert witnessing isn’t for the faint-hearted. The atmosphere in the courtroom can feel formal and intense. All eyes are on you while you speak. Your questioning usually happens in two stages:

1. The attorneys’ direct examination is when you tell your story. You explain your credentials, how you were hired, what you did, what you found and what conclusions you reached. This is your chance to be clear, logical and persuasive — showing that your opinion is grounded in solid facts and reliable methods.
2. Cross-examination by the opposing attorney can be stressful. Their job is to poke holes in your credibility, methods or conclusions. They may ask yes-or-no questions. They may try to rush you and highlight any inconsistencies. You must stay calm, listen carefully, think before you speak and never argue. If you don’t know an answer, you say so, because guessing or being defensive can destroy your credibility.

The best expert witnesses remember that credibility is everything. If you’re honest, objective and stick to what you truly know, you’ll withstand tough questioning, and the jury will trust you more for it.