Tort law II
Part of the common law series
Negligent torts
Negligence  · Negligent hiring
Negligent entrustment
Negligent infliction of emotional distress
Doctrines affecting liability
Duty of care  · Standard of care
Proximate cause  · Res ipsa loquitur
Calculus of negligence  · Eggshell skull
Vicarious liability  · Attractive nuisance
Rescue doctrine  · Duty to rescue
Comparative responsibility
Duties owed to visitors to property
Trespassers  · Licensees  · Invitees
Defenses to negligence
Contributory negligence
Comparative negligence
Assumption of risk  · Intervening cause
Strict liability
Ultrahazardous activity
Products liability
Nuisance
Other areas of the common law
Contract law  · Property law
Wills and trusts
Criminal law  · Evidence

In the United States, the calculus of negligence or "learned hand rule" is a term coined by Judge Learned Hand and describes a process for determining whether a legal duty of care has been breached (see negligence). The original description of the calculus was in U.S. v. Carroll Towing, 159 F.2d 169 (2d Cir. 1947), which alleged that a boat was improperly secured and caused damage. Hand stated: Image File history File links SmallLadyJustice. ... In the common law, a tort is a civil wrong, other than a breach of contract, for which the law provides a remedy. ... This article concerns the common-law legal system, as contrasted with the civil law legal system; for other meanings of the term, within the field of law, see common law (disambiguation). ... In law, negligence is a type of tort or delict that can be either criminal or civil in nature. ... Negligent hiring is a cause of action in tort law that arises where one party is held liable for negligence because they placed another party in a position of authority or responsibility, and an injury resulted because of this placement. ... Negligent entrustment is a cause of action in tort law that arises where one party (the entrustor) is held liable for negligence because they negligently provided another party (the entrustee) with a dangerous instrumentality, and the entrusted party caused injury to a third party with that instrumentality. ... The tort of negligent infliction of emotional distress (NIED) is a controversial legal theory and is not accepted in many United States jurisdictions. ... In law, a duty of care is the legal requirement that a person exercise a reasonable standard of care to prevent injury of others. ... In tort law, the standard of care is the degree of prudence and caution required of an individual who is under a duty of care. ... In the law, a proximate cause is an event sufficiently related to a legally recognizable injury to be held the cause of that injury. ... Res ipsa loquitur is a legal term from the Latin meaning literally, The thing speaks for itself. The doctrine is applied to claims which, as a matter of law, do not have to be explained beyond the obvious facts. ... The eggshell skull rule (or thin-skull rule) is a legal doctrine used in both tort law and criminal law that holds an individual liable for all consequences resulting from their activities leading to an injury to another person, even if the victim suffers unusual damages due to a pre... Vicarious liability is a form of strict, secondary liability that arises under the common law doctrine of agency – respondeat superior – the responsibility of the superior for the acts of their subordinate and can be distinguished from contributory liability, another form of secondary liability, which is rooted in the tort theory... Under the attractive nuisance doctrine of the law of torts, a landowner may be held liable for injuries to children trespassing on the land if the injury is caused by a hazardous object or condition on the land that is likely to attract children, who are unable to appreciate the... The rescue doctrine of the law of torts holds that, where a tortfeasor creates a circumstance that places the tort victim in danger, the tortfeasor is liable not only for the harm caused to the victim, but also the harm caused to any person injured in an effort to rescue... A duty to rescue is a concept in the law of torts that arises in a narrow number of cases, describing a circumstance in which a party can be held liable for failing to come to the rescue of another party in peril. ... Comparative responsibility is a doctrine of tort law that compares the fault of each party in a law suit for a single injury. ... Trespasser (released in 1998) was a game taking place in the world of Jurassic Park. ... A licensee is a term used in the law of torts to describe a person who is on the property of another, despite the fact that the property is not open to the general public, because the owner of the property has allowed the licensee to enter. ... An invitee is a term used in the law of torts to describe a person who is on the property of another because that property owner has chosen to hold the property open to some portion of the general public, because the owner of the property has allowed the licensee... Contributory negligence is a common law defence to a claim or action in tort. ... Comparative negligence is a system of apportioning recovery for a tort based on a comparison of the plaintiffs negligence with the defendants. ... This is a defense in the law of torts. ... An intervening cause is a potential defense to the tort of negligence, if it is an unforseeable, and therefore superseding intervening cause, rather than a foreseeable intervening cause. ... Strict liability is a legal doctrine in tort law that makes a person responsible for the damages caused by their actions regardless of culpability (fault) or mens rea. ... An ultrahazardous activity in the common law of torts is one that is so inherently dangerous that a person engaged in such an activity can be held strictly liable for injuries caused to another person, even if the person engaged in the activity took every reasonable precaution to prevent others... Product liability encompasses a number of legal claims that allow an injured party to recover financial compensation from the manufacturer or seller of a product. ... Nuisance is a common law tort. ... A contract is a promise or an agreement that is enforced or recognized by the law. ... Property law is the area of law that governs the various forms of ownership in real property (land as distinct from personal or movable possessions) and in personal property, within the common law legal system. ... In the common law, a will or testament is a document by which a person (the testator) regulates the rights of others over his property or family after death. ... The law of trusts and estates is generally considered the body of law which governs the management of personal affairs and the disposition of property of an individual in anticipation and the event of such persons incapacity or death, also known as the law of successions in civil law. ... Criminal law (also known as penal law) is the body of common law that punishes criminals for committing offences against the state. ... The law of evidence governs the use of testimony (e. ... Billings Learned Hand (January 27, 1872 – August 18, 1961) — usually called just Learned Hand — was a famed American judge and an avid supporter of free speech, though he is most remembered for applying economic reasoning to American tort law. ... In law, negligence is a type of tort or delict that can be either criminal or civil in nature. ... United States v. ... // Case citation is the system used in common law countries such as the United States, England and Wales, Canada, New Zealand Australia and India to uniquely identify the location of past court cases in special series of books called reporters. ... The United States Court of Appeals for the Second Circuit is a federal court with appellate jurisdiction over the following United States District Courts: District of Connecticut Northern, Southern, Eastern, and Western Districts of New York District of Vermont The Second Circuit hears argument at the Thurgood Marshall U.S... 1947 (MCMXLVII) was a common year starting on Wednesday (the link is to a full 1947 calendar). ...

[T]he owner's duty, as in other similar situations, to provide against resulting injuries is a function of three variables: (1) The probability that she will break away; (2) the gravity of the resulting injury, if she does; (3) the burden of adequate precautions.

This relationship has been formalised by the law and economics school as such: an act is in breach of the duty of care if: Law and economics is the term usually applied to an approach to legal theory that incorporates methods and ideas borrowed from the discipline of economics. ...

B < PL

where B is the cost (burden) of taking precautions, and P is the probability of loss (L). L is the loss. The product of P x L must have a greater amount compared to the burden of taking precautions. If it is greater, this creates a duty for the defendant.

It has been severely criticized that imposing liability based on a calculation is flawed. It is taking into the burden even if the there was no reasonable foreseeable duty. Duty is created by the foreseeability factors and forcing a calculation to create a duty would be unjust.

Rationale

The calculus of negligence is based on the Coase theorem. The tort system acts as if, before the injury or damage, a contract had been made between the parties under the assumption that a rational, cost-minimizing individual will not spend money on taking precautions if those precautions are more expensive than the costs of the harm that they prevent. In other words, rather than spending money on safety, the individual will simply allow harm to occur and pay for the costs of that harm, because that will be more cost-efficient than taking precautions. This represents cases where B is greater than PL. In law and economics, the Coase theorem, attributed to Ronald Coase, relates to the economic efficiency of a governments allocation of property rights. ... Rational may be: the adjective for the state of rationality acting according to the philosophical principles of rationalism a mathematical term for certain numbers; the rational numbers the software company Rational Software; now owned by IBM, and formerly Rational Software Corporation This is a disambiguation page — a navigational aid which...

If the harm could be avoided for less than the cost of the harm (B is less than PL), then the individual should take the precautions, rather than allowing the harm to occur. If precautions were not taken, we find that a legal duty of care has been breached, and we impose liability on the individual to pay for the harm.

This approach, in theory, leads to an optimal allocation of resources; where harm can be cheaply avoided, the legal system requires precautions. Where precautions are prohibitively expensive, it does not. In marginal-cost terms, we require individuals to invest one unit of precautions up until the point that those precautions prevent exactly one unit of harm, and no less.