CASUALTY TERMS & CONCEPTS · 5 MIN READ

Negligence Elements, Standards of Care, and Proof

Negligence is the backbone of casualty insurance because liability policies respond to legal liability, and legal liability usually means negligence. A negligence claim has four elements: the defendant owed a duty of care, breached that duty, the breach factually and proximately caused harm, and the plaintiff suffered damages. Breach is measured against the reasonable person — an objective standard that flexes in defined ways. Children are judged as a reasonable child of like age, intelligence, and experience, unless the child is engaged in an inherently dangerous adult activity such as driving a car or boat, in which case the adult standard applies. Many states also presume children of tender years (often under seven) incapable of negligence. An actor confronting a sudden emergency is judged by what a reasonable person would do in that emergency. Courts also use structured tools to decide breach. Judge Learned Hand's formula from United States v. Carroll Towing frames breach as economics: a defendant is negligent when the burden of precaution (B) is less than the probability of loss (P) multiplied by the magnitude of the potential loss (L) — negligence exists when B is less than P times L. Negligence per se borrows a safety statute as the standard of care: under the majority approach, an unexcused violation of a statute conclusively establishes breach when the statute was designed to protect the class of persons that includes the plaintiff against the type of harm that occurred; the plaintiff still must prove causation and damages. When the plaintiff cannot point to the specific negligent act, res ipsa loquitur lets the jury infer negligence from circumstances. Three elements are required: the accident is of a kind that ordinarily does not happen without negligence, the instrumentality was in the defendant's exclusive control, and the plaintiff did not contribute to the event. In most states the doctrine creates a permissible inference; in some, a rebuttable presumption. In medical malpractice, the standard-of-care fight adds the locality rule versus national standard debate and the informed-consent requirement to disclose material risks.