Engineering Expert Witness Qualifications: What Matters

Article By Nathan Macdonald, PE, CSP

At the very beginning of an expert witness engagement, it is easy to go looking for a unicorn. You have a case with a fairly niche subject, a disclosure deadline on the calendar, and what you would really like is someone who has spent an entire career on exactly the product at issue and has also been through deposition and trial a few dozen times. That person may exist. Often, they do not, and the task becomes evaluating how much of each quality a candidate brings, and how much of each the case actually needs.

Among the things attorneys weigh in an engineering expert, two deserve significant attention at the outset: the technical qualifications to analyze the issues, and the ability to develop, explain, and defend those opinions under the scrutiny litigation brings. This article is about how to evaluate each, how to weigh them against your case, and what to ask before you retain.

For reference, I have spent more than a decade in consulting engineering and expert witness work, and have been deposed and have testified at trial in product liability and patent matters. I would expect to be measured against the same criteria.

There are many dimensions to consider in choosing an expert, but this article will focus on:

1. The candidate’s subject matter expertise
2. The candidate’s expert witness experience

These are different qualifications, and they should be evaluated separately rather than combined into a single impression. A highly specialized engineer with no litigation experience may know the product thoroughly but not yet know how to present an opinion that survives cross-examination. Extensive testifying experience cannot compensate for qualifications that are insufficient for the opinions the case requires.

Technical qualifications establish whether an expert is suited to address the issues in a case. Litigation experience is an additional measure of how effectively that expert may develop, explain, and defend those opinions.

In federal court, under Federal Rule of Evidence 702, an expert must be qualified by knowledge, skill, experience, training, or education. The testimony must help the trier of fact understand the evidence or determine a fact at issue, and it must rest on sufficient facts or data and on reliable principles and methods, reliably applied to the facts of the case. The 2023 amendment to the rule made explicit that the proponent must show these requirements are more likely than not met.

Qualification in the subject matter is therefore the threshold, not a preference. Evaluate technical qualifications first, and once that bar is cleared, weigh the candidate’s litigation experience.

An engineering expert witness should have technical knowledge and experience relevant to the opinions required, familiarity with the applicable engineering methods and standards, and the ability to support conclusions through reliable analysis.

The practical question is what “enough” subject matter expertise looks like. The test is relevant, demonstrable expertise with the engineering at issue, whether from experience, training, or education, not necessarily years spent on the identical product. Design principles, failure modes, materials behavior, and the way standards are written and revised are shared across product categories.

An engineer who has designed, analyzed, and tested products in the relevant category, or a closely related one, may have the technical foundation to evaluate the issues, provided that experience applies to the specific opinions being offered. What the expert must be able to show, in the report and on the stand, is the specific basis for that familiarity: the systems they have designed, the failure modes they have analyzed, the standards they have worked under. “I can learn it” is not a qualification. “I have designed and tested systems that work on the same principles, and here is how” is.

When reviewing a candidate’s background, look for:

• Hands-on design, analysis, or testing experience with the product category or a closely related one. The underlying engineering usually matters more than the exact model.
• Working familiarity with the standards that govern the product, including how editions and effective dates work.
• The ability to design and run tests whose results will hold up, not just to review someone else’s.
• Relevant professional credentials, such as PE licensure or CSP certification, where they apply to the subject matter and the scope of the proposed opinions.
• Potential conflicts of interest, including prior engagements, confidential information, or professional relationships that could affect the expert’s independence or availability.

There are cases where a specialist’s depth is indispensable. Highly regulated or specialized fields, such as medical devices or aerospace, may demand direct experience that a generalist cannot acquire from the case file. In those situations the right structure may be a specialist for the technical opinion, supported by additional engineering resources for testing and analysis, with each person staying within their own qualifications.

Expert witness experience is more than a record of depositions and trial appearances. In my experience, its value often comes down to two things: learning to recognize and examine the assumptions behind an opinion, and developing the ability to communicate technical findings precisely.

Answering a colleague in a design review who wants you to be right is one thing. Answering the same question from someone whose job is to find where you are wrong is another. That scrutiny can teach an expert to distinguish between what the evidence supports and what they may believe to be true, and to communicate their conclusions with greater precision.

An engineer who has encountered these challenges may be better prepared to address them during the analysis and report preparation, rather than for the first time during testimony.

Litigation experience does not guarantee stronger opinions, but it can influence how an expert approaches the evidence, evaluates alternative explanations, and communicates conclusions.

Engineering experts may encounter challenges involving the applicability of standards, testing methods, and the basis for their opinions. Prior litigation experience can help an expert recognize and address some of these issues early. The following examples illustrate situations in which careful documentation and analysis are particularly important.

1. Standard editions. Citing the current edition of a standard because the relevant clause has not changed. The applicable edition depends on the question being answered and the governing requirements, which may point to the edition in effect when the equipment was designed, manufactured, or sold. Even if the language is identical, the cite should match the applicable edition and the report should say why.
2. Exemplar testing. Testing an exemplar that is representative of the incident equipment without documenting that it matches in the characteristics material to the analysis. The counterargument is predictable: the exemplar was never shown to be the same in the respects that matter.
3. Voluntary standards. Treating a voluntary consensus standard as settled without explaining its role. Depending on the standard and the case, voluntary consensus standards may provide evidence of industry practice or safety expectations. The report needs to explain the standard’s relevance, applicability, and technical significance rather than assume those points are established.
4. Best practice. Appealing to “best practice” in a lightly regulated industry without a basis for it. The conclusion may be correct, but “it should be done this way” is not a basis. Published guidance, test data, comparable standards from adjacent industries, or engineering analysis is.

When any of these comes up, the argument shifts away from the engineering questions, what happened, what conditions contributed, and whether the identified hazards could reasonably have been addressed, to whether the right edition or the right exemplar was used. Those details matter and should be right. An experienced expert is likely to address them in the report before they become the argument, so the case stays focused on the central question.

Nathan Macdonald, PE, CSP, is a licensed professional mechanical engineer and Certified Safety Professional at Alpine Engineering & Design in Alpine, Utah. His engineering experience spans mobile hydraulic equipment, including aerial boom lifts and scissor lifts; amusement and recreational devices; exercise and fitness equipment; and consumer and industrial products with mechanical, electrical, and hydraulic systems. He is a named inventor on a U.S. patent and serves as an expert witness in product liability, premises liability, and patent matters, where he has been deposed and has testified at trial.

Alpine Engineering & Design is a mechanical engineering firm in Alpine, Utah, providing expert witness services nationwide in product liability, patent, and intellectual property litigation, alongside product development, design analysis, and machine safety engineering. Its team includes licensed professional engineers and Certified Safety Professionals who design and test products as well as testify about them. If you have a case coming up and are working out who to retain, request a consultation. The team will talk through whether Alpine is the right fit for the case, and say so if it is not.

1. Federal Rule of Evidence 702, Testimony by Expert Witnesses, as amended Dec. 1, 2023. Legal Information Institute, Cornell Law School.