Defences

Defences to the tort of negligence are typically contributory negligence, voluntary assumption of risk, or illegality.

In the case of contributory negligence, the plaintiff is judged to be partly responsible for the loss incurred and, therefore, the plaintiff’s damages will be reduced to the extent of the contributory negligence.

For voluntary assumption of risk, the plaintiff is judged to have freely agreed to accept the risk of injury or loss. In contrast to contributory negligence, which is a partial defence, voluntary assumption of risk is a complete defence that would result in the defendant not being held liable. For instance, parking garages usually post signs to indicate that people who park there do so at their own risk.

Another complete defence is that the plaintiff suffered a loss while participating in an illegal act, which will also exonerate the defendant from liability.

Product Liability

Product liability (manufacturer’s liability) is the standard of care imposed on manufacturers in relation to the design, manufacture, and/or sale of their products. It is one of two important torts of negligence that warrant separate attention. Product liability also gives rise to actions for breach of contract; however, end consumers do not typically have a contractual relationship with manufacturers, limiting their recourse to retailers.

Pursuant to the case of Donoghue v. Stevenson, under the principle of res ipsa loquitur (the facts speak for themselves), if a product is defective, then it can reasonably be assumed that there has been negligence at some stage of its design, production, or inspection, and the onus is now on the manufacturer to prove that it took due care at all stages to try to prevent defective goods from reaching the distribution system. This duty has also been extended to other businesses in the distribution chain. In the United States, liability is not limited to cases of negligence; rather strict liability is often found, making the manufacturer liable for injury regardless of efforts taken to prevent faulty products from reaching the consumer.

More recent cases—Lambert v. Lastoplex Chemical Co. Ltd. (1972; inflammable lacquer) and Buchan v. Ortho Pharmaceutical (Canada) Ltd. (1984; side effects of contraceptive pills)— impose a duty on Canadian manufacturers to give consumers proper warning when, even though a product may not be defective, dangers may arise if the product is not properly used. In the 1995 case Hollis v. Dow Corning Corp., the Supreme Court of Canada made it clear that the duty to warn is a continuing one so that if, after a product has been placed on the market, the manufacturer becomes aware of potential dangers in its use, it must issue appropriate warnings to the public. The Court also ruled that the duty to warn may be discharged in some cases by issuing the warning to "learned intermediaries" like surgeons who use silicone breast implants. If the plaintiff’s claim is based on a failure to warn, she must prove that she would not have used the product or would not have used it the way she did had proper warning been given. In other words, the failure to warn must have caused the injury.

Professional Liability

Professionals have specialized knowledge and skills that clients rely on and are willing to pay for. The value of professional services lies not in their infallibility but in their capacity to reduce risk for the client. In defining liability for professional incompetence or negligence, the courts have tried to balance the social objective of assisting innocent victims with the need to avoid discouraging legitimate professional activity. A professional's duty of care may arise from one of three possible sources:

1. Contractual duty: An agreement to provide professional services to a client implies a certain duty of care. More will be said about this under contract law.

2. Fiduciary duty: Equity imposes a duty of care on a person who stands in a special relationship of trust to another, as in the professional-client relationship. It is a higher duty of care than that owed under a contract since it requires complete fidelity and loyalty and may be breached even though there has been no negligence. Examples of obligations imposed on the professional include avoiding conflicts of interest; refraining from using the relationship for personal profit; following the client’s instructions; disclosing all relevant information to the client; acting honestly, in good faith, and with due care; and maintaining confidentiality.

3. Duty in tort: A duty of care is imposed by tort law to a much broader class of people than under contractual duty. A duty in tort also imposes a time limit for tort action from the moment the breach is discovered (as opposed to the moment the breach occurs, as in contract law). The form of action chosen may also affect the amount of damages. Plaintiffs may choose to “cover the bases” by pleading all three causes of action.

Standard of Care for Professionals under Tort Law

The standard of care imposed on a professional in a tort action is as follows:

1. Professionals are held to the standard of a reasonable professional in similar circumstances. This includes living up to their training (regardless of how inexperienced they might be) but depends on whether they are a specialist or generalist.

2. The standard of care is based on the information reasonably available to the defendant in foresight, not in hindsight.

3. Carelessness results in liability while an error of judgment does not.

4. A professional who follows an approved practice cannot be found liable.

5. Compliance with a statutory standard will be considered in deciding whether a professional acted with reasonable care.

Third-Party Liability and the Tort of Negligent Misrepresentation

Under tort law, potential third-party liability exists to people other than the client who pays for the services and has a contractual relationship with the professional. For instance, accountants may provide a business valuation that will be relied upon by a third party, or architects may design a building in a way that presents risks to subsequent occupants.

Hedley Byrne Co. Ltd. v. Heller & Partners Ltd. (1964) established the principle that professionals are liable for negligent misrepresentation (an incorrect statement made without due care for its accuracy) to third parties whom they could foresee would rely on information or advice they provide. Haig v. Bamford (1976) narrowed that duty to a limited class of persons with whom the professional has a special relationship. Thus the test is not just that users must be foreseeable in a general sense but that they must be specifically foreseeable in relation to a contemplated transaction.

Causation as a Requirement for Liability Under Tort Law

As is the case with negligence in general, a duty of care owed to the plaintiff and a breach of that duty are necessary but not sufficient conditions for liability. There must also be a clear causal link between the breach of the duty by the defendant and the injury suffered by the plaintiff. A plaintiff must have relied on the negligent misrepresentation before that misrepresentation can be said to have "caused" the plaintiff's loss. Reliance includes the willing cooperation of the plaintiff—an element not present in the commission of most torts. Therefore, proving causation is a subtle feat since a whole host of factors may enter into someone's decision, say, to buy shares, make a loan, buy a house, or undergo surgery.