Industry custom and practice expert
Expert class library · Commercial · Either side
Explains how a particular trade customarily operates, such as how agreements are formed, what terms are standard, and how commissions or policy limits are usually handled, so the factfinder can interpret contracts and judge conduct in context. Because the opinion rests on experience rather than a formal method, courts focus on whether that experience covers the specific practice at issue and bar experts from telling the jury what the contract means or who should win.
What this expert is retained to answer
- What was the custom and practice in this industry for the type of agreement or transaction at issue?
- Is a particular term, such as commissions for the life of a part or an aggregate limit, customarily included or implied?
- How do participants in the trade understand a term of art used in the contract?
- Did the parties' conduct conform to what is usual in the industry?
- How widespread and consistent is the claimed practice, and what sources corroborate it?
Methods
- Trade usage analysis
- Contract term interpretation in context
- Comparison to industry norms
- Experience-based opinion
How the testimony is attacked
- Experience that does not match the specific practice. Opponents argue general industry or legal experience does not establish expertise in the particular custom at issue. In Bill Barrett v. YMC Royalty the Tenth Circuit affirmed exclusion of an oil and gas attorney who failed to show expertise in the industry practice for joint operating agreements.
- Legal conclusions dressed as custom. Challengers argue the expert is really telling the jury how to read the contract or apply the law. The Bill Barrett trial court barred legal opinions while tentatively allowing custom testimony, and in Jesa Enterprises v. Thermoflex the court barred both sides' experts from saying which party should win.
- Opinion based only on the pleadings. Defendants argue the expert relied on the complaint rather than independent industry knowledge. The Jesa court held that each side's expert satisfied Rule 702 on custom and practice through long experience negotiating and reviewing industry agreements.
- Unsupported or contradicted custom. Opponents point to documents inconsistent with the claimed practice. In Utica Mutual v. Fireman's Fund the court admitted the insurer's custom expert because his review of thousands of policies and third-party sources corroborated the practice, leaving contrary evidence for cross-examination.
- Irrelevant moral or policy views. Experts sometimes add views about what is fair. The Jesa court excluded one expert's moral position on post-termination commissions as unhelpful to the factfinder.
What the public record shows
A deliberately narrow CourtListener search, "custom and practice" AND industry AND "expert testimony" AND (Daubert OR "Rule 702"), returned 22 opinions filed since 2015, as of October 2, 2026; broader searches return more. Three that show how courts handle this class of testimony:
| Outcome | Case | Court | Why |
|---|---|---|---|
| Excluded | Bill Barrett Corporation v. YMC Royalty Company918 F.3d 760 | 10th Cir. 2019 | The Tenth Circuit affirmed the trial court's Rule 702 exclusion of the defendant's oil and gas attorney offered on industry custom and practice because the defendant did not establish his expertise in the specific practice of using joint operating agreements. |
| Limited | Jesa Enterprises Ltd. v. Thermoflex Corp.268 F. Supp. 3d 968 | E.D. Mich. 2017 | The court allowed both sides' experts to testify on automotive industry custom for paying sales representatives commissions for the life of a part, but barred them from telling the jury which party should prevail because that was a legal conclusion. |
| Admitted | Utica Mutual Insurance Co. v. Fireman's Fund Insurance Co.238 F. Supp. 3d 314 | N.D.N.Y. 2017 | The court denied the motion to preclude the insurer's expert on industry custom regarding aggregate limits in products liability policies, finding his decades of experience and corroborating third-party sources made the opinion reliable and helpful. |
Each case links to the free opinion text on CourtListener.
Under amended Rule 702
Since December 1, 2023, Rule 702 says expressly that the party offering an expert must show the court it is more likely than not that the testimony meets each requirement: that it rests on sufficient facts or data, uses reliable methods, and reflects a reliable application of those methods to the case. Questions about the basis of an opinion are no longer automatically matters of weight for the jury. For how the circuits have applied the amendment, see the Rule 702 tracker, which follows each court of appeals; for what that means for preparing or attacking this class of expert, see the guide on amended Rule 702.
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Last reviewed October 2, 2026. How this page is built: rulings are found by searching court opinions on CourtListener, and each one is read in the opinion before it is summarised here; outcomes are labelled by what the court did with the expert's testimony. No individual expert is named. This page summarises public decisions for orientation and is not legal advice; read the opinion before relying on any ruling.