Free tool · Tort Law
Is It Negligence?
Negligence is a failure to take reasonable care that causes harm to someone to whom you owed a duty. To win, a plaintiff must show five things: a duty of care, a breach of it, that the breach was an actual cause of the harm, that it was a proximate (legally responsible) cause, and real damages. The Hand formula is a helpful way to think about breach: a precaution is called for when its cost is less than the probability of the harm multiplied by its size. Answer the questions below to see which element succeeds, and which is in doubt.
Tool · Negligence Analyzer
All five elements of negligence appear to be satisfied.
Duty: Everyone owes a duty of reasonable care to foreseeable plaintiffs not to create an unreasonable risk of harm to them (Palsgraf v Long Island Railroad: the duty runs to those within the zone of foreseeable danger).
Breach: On the Hand formula (United States v Carroll Towing), the precaution cost 200 is less than the expected loss avoided (0.1 × 5,000 = 500), so failing to take it is unreasonable.
Actual cause: But for the defendant’s act, the harm would not have occurred (the but-for test).
Proximate cause: The harm was within the scope of the risk that made the conduct negligent, so the defendant is legally responsible for it. The ‘eggshell plaintiff’ rule makes the defendant liable for the full extent of an unusually vulnerable plaintiff’s injury.
Damages: The plaintiff suffered real, provable harm: negligence, unlike an intentional tort, requires actual damage.
No plaintiff fault is alleged. Other defences to check: assumption of risk, statute of limitations, and immunities.
- Turn to defences, and to the measure of damages.
Walks through the five elements of negligence (duty, breach, actual cause, proximate cause and damages), with the Hand formula as a way of thinking about breach: a precaution is called for when its cost is less than the probability of harm times the size of the loss. Simplified general American rules, which differ between states. A teaching aid, not a prediction of how a court would decide a real case, and not legal advice. Runs in your browser; nothing is stored or sent.
How to use it
- Say whether a duty was owed, and why.
- Enter the cost of the precaution, the probability of harm and the size of the loss to apply the Hand formula, or tick negligence per se or res ipsa loquitur.
- Say whether the harm would have happened anyway, whether it was within the scope of the risk, and whether anything unforeseeable intervened.
- Read each element, and what to look at next.
Common questions
What are the elements of negligence?
Duty, breach, actual cause (cause in fact), proximate cause (legal cause) and damages. The plaintiff must prove all five.
What is the Hand formula?
From United States v Carroll Towing: a party is negligent if the burden of the precaution (B) is less than the probability of harm (P) multiplied by the gravity of the loss (L), that is, B < PL. It is a way of reasoning about reasonableness, not the legal test itself.
Is there a duty to rescue a stranger?
Generally not. A stranger has no duty to help, even when rescue would be easy, unless there is a special relationship, the defendant created the peril or has begun to help.
Learn the law behind the tool
This tool is part of our Tort Law course, with lectures, concept maps, flashcards, interactive exercises and a capstone case. Tort Law: Negligence, Duty and Breach.
More free law tools
General information, simplified, mainly on American law, not legal advice. States and countries differ, and real cases turn on facts that a tool cannot capture.