Glossary · Doctrine
Industry Custom
The prevailing practice of a profession or industry, used as evidence of (but not conclusive proof of) the standard of care under the doctrine of T.J. Hooper.
Also known as: customary practice, industry standard practice
What it is
Industry custom refers to the prevailing, generally accepted practice within a profession at the time of an alleged tort. In a malpractice case, it is what most reasonably competent practitioners in the relevant specialty actually do under similar circumstances. Custom is established through expert testimony, professional society guidelines, published practice standards, and survey evidence.
Custom is evidence, not a complete defense
Under The T.J. Hooper (2d Cir. 1932) and its progeny, industry custom is admissible as evidence of reasonable care but does not by itself conclusively establish that conduct was non-negligent. An entire industry can lag behind reasonable prudence by failing to adopt safer, available practices. The trier of fact may find that conformity with custom was nonetheless unreasonable.
How it differs in malpractice
Medicine occupies a special position because courts have historically been more deferential to professional custom than in ordinary tort cases. In some jurisdictions, the standard of care is essentially defined as what other practitioners customarily do; in others (especially after Helling v. Carey), courts apply Hooper-style scrutiny and ask whether the customary practice itself was reasonable.
Why it matters now
The gap between custom and reasonable prudence is widening as medical technology evolves. Diagnostic AI, advanced imaging, and decision-support tools are available but not yet customary. Plaintiff counsel increasingly argue that failure to use these tools breaches the duty of care even when the broader profession has not yet adopted them. The Hooper doctrine is the legal foothold for that argument.
In settlement strategy
Defense counsel should identify and document the customary practice early. Plaintiff counsel should be ready to show that the customary practice itself was unreasonable in light of available alternatives.
See Also
- T.J. Hooper — The 1932 Second Circuit case (60 F.2d 737) in which Judge Learned Hand held that an entire industry's customary practice can itself be unreasonably negligent if better, available safety measures are ignored.
- Standard of Care — The level of skill, diligence, and judgment a reasonably competent practitioner in the same specialty would exercise under similar circumstances, used as the benchmark for proving negligence in a malpractice case.
- Breach of Duty — The element of a negligence claim that requires the plaintiff to prove the defendant's conduct fell below the applicable standard of care.