Negligence: breach and the standard of care 

Breach asks two questions in order: what standard of care did the law require, and did the defendant's conduct fall below it? They are different questions and answering them together produces a muddled answer.

The standard

The standard is that of a reasonable person in the defendant's position. It is objective: the defendant's own good intentions, inexperience or best efforts are beside the point. A learner driver is held to the standard of a competent driver.

Two adjustments are recognised. A child is judged by the standard of a reasonable child of comparable age, and a person professing a special skill is judged by the standard of a person exercising that skill.

The statutory test

The civil liability statutes state the test in a common form: a person is not negligent in failing to take precautions against a risk unless the risk was foreseeable, the risk was not insignificant, and a reasonable person in the person's position would have taken those precautions.

Two things to notice. First, "not insignificant" is deliberately a higher threshold than the common law's "not far-fetched or fanciful", and it is the reason foreseeability at breach is not the same enquiry as foreseeability at duty. Second, the statute directs attention to precautions — a plaintiff who cannot identify what the defendant should have done has not made out breach, however serious the injury.

The calculus of negligence

Wyong Shire Council v Shirt (1980) 146 CLR 40¹ is the source of this framework, later codified in the civil liability statutes. In deciding what a reasonable person would have done, the court weighs:

• the probability that the harm would occur if care were not taken;
• the likely seriousness of the harm;
• the burden of taking precautions to avoid the risk;
• the social utility of the activity that creates the risk.

Work from the statute where one applies. In Adeels Palace Pty Ltd v Moubarak (2009) 239 CLR 420² the Court set out s 5B of the Civil Liability Act 2002 (NSW) in full at [13] and warned that the "Duty of care" heading above it "is apt to mislead" — these are breach provisions. Note what s 5B(1) requires before a failure to take precautions can be negligent: that the risk was not insignificant. Whether that is the same test Shirt states is a question this case does not address, so do not cite it for the comparison; check which statutory provision applies in your jurisdiction, because they differ.

The statutes list these factors and make clear the list is not exhaustive. Two disciplines matter in applying them:

1. Reason prospectively. The question is what a reasonable person would have done before the injury, not what is obvious once it has happened. Hindsight bias is the standard trap and the statutes warn against it.
2. The burden is the burden of the precaution, not of the accident. A cheap precaution against a small risk of grave harm will usually be required; an expensive one against a remote risk of minor harm will not.

Compliance with common practice is evidence of reasonable care, not proof of it — a whole industry can be negligent.

Professionals

A professional is judged by the standard of the ordinarily skilled member of that profession. Most jurisdictions add a statutory peer professional opinion defence: a professional does not breach the duty if they acted in a manner widely accepted by peer professional opinion as competent professional practice, unless the court considers that opinion irrational.

The crucial carve-out is that this defence does not apply to the duty to warn of, or give information about, a risk. Whether a patient or client was adequately informed is decided by the court, not by professional practice — a rule Australia settled well before the statutes and preserved in them. Confusing the treatment standard with the information standard is a frequent and costly error.

Obvious and inherent risks

The statutes provide that there is generally no duty to warn of an obvious risk — one that would have been obvious to a reasonable person in the plaintiff's position — subject to exceptions such as a request for advice or a professional risk of death or personal injury from treatment. They also provide that no liability arises for the materialisation of an inherent risk, one that cannot be avoided by reasonable care.

These provisions are jurisdiction-specific in their detail and interact with the defences of obvious risk and dangerous recreational activity.

Proving breach

The plaintiff bears the onus on the balance of probabilities. Where the accident is of a kind that does not ordinarily happen without negligence and the thing causing it was under the defendant's control, an inference of negligence may be drawn. That reasoning is a permissible inference, not a rule that shifts the legal onus.

Applying this in a problem question

1. State the standard, adjusted for age or special skill.
2. Identify the precaution the plaintiff says should have been taken. Be specific.
3. Work through the statutory test: foreseeable, not insignificant, and would a reasonable person have taken that precaution.
4. Apply the calculus factors that carry weight on the facts, prospectively.
5. For professionals, address peer professional opinion — and exclude it if the complaint is a failure to warn.
6. Consider obvious and inherent risk before turning to defences.

Where the authority sits

The civil liability statute of the relevant jurisdiction states the test, and the common law supplies the calculus and the standard it restates. The wording differs between jurisdictions and the differences occasionally matter, so identify the jurisdiction before stating the test.