Negligence
Rule
A defendant is liable for negligence when: (1) the defendant owed a duty of care to the plaintiff; (2) the defendant breached that duty by failing to act as a reasonably prudent person would under the circumstances; (3) the breach was the actual and proximate cause of the plaintiff’s harm; and (4) the plaintiff suffered actual damages.
Elements
- Duty — The defendant owed the plaintiff a legal obligation to exercise reasonable care.
- Breach — The defendant failed to meet the standard of care (the Reasonably Prudent Person, or RPP).
- Actual causation — But for the defendant’s breach, the plaintiff’s harm would not have occurred.
- Proximate causation — The harm was a foreseeable consequence of the breach (no superseding cause breaks the chain).
- Damages — The plaintiff suffered actual harm (personal injury, property damage, or recognized economic loss).
Exceptions / Modifications to Standard of Care
- Physical disability: held to the standard of a person with that disability.
- Children: held to the standard of a child of like age, knowledge, and experience (except for adult activities).
- Professional/superior attributes: held to the higher standard of the profession (e.g., medical malpractice).
- Mental disability: objective RPP standard maintained.
- Emergency doctrine: RPP under the sudden and unforeseeable circumstances.
The Hand Formula (B < PL)
From Carroll Towing Co. (Learned Hand, J.): negligence exists when the Burden of adequate precaution (B) is less than the Probability of injury (P) multiplied by the magnitude of Loss (L). A cost-benefit balancing test for breach.
Policy
- Deterrence: incentivizes actors to internalize the costs of their carelessness.
- Compensation: shifts losses to the responsible party.
- Loss-spreading: through insurance and pricing.
- Predictability: objective standard creates a community norm that people can conform to and plan around.
- The objective RPP standard promotes administrative convenience but may sacrifice individual fairness (Vaughn).
Key Cases
- United States v. Carroll Towing Co. — articulates the B < PL Hand Formula for breach.
- Palsgraf v. Long Island Railroad — defines duty as specific and relational (Cardozo), limiting liability to foreseeable plaintiffs.
- Adams v. Bullock — harm must be foreseeable; no negligence when risk is not reasonably anticipatable.
- Hammontree v. Jenner — negligence (not strict liability) is the correct standard for sudden incapacity while driving.