a. Standard of care
The standard of care is objective. The court asks what a reasonable person in the defendant’s position at the time of the incident — for example, a reasonable driver, employer, doctor, contractor, or occupier — would have done.
The standard of care is based on foresight, not hindsight. A defendant is judged according to the state of scientific and technical knowledge prevalent at the time of the alleged breach. The “reasonable man” is not expected to know things that have not yet been discovered by the relevant profession or industry.
However, a defendant cannot avoid liability by arguing he “did his best” if that best falls below the objective standard.
In assessing whether the standard has been met, the court considers a number of practical factors, including:
- How likely the harm was.
- How serious the harm could be.
- How easy or costly it would have been to take precautions.
- Whether the activity was urgent or carried social value.
- Whether any regulations, safety codes, or common practice were followed.
(i) Likelihood of harm
A defendant is not required to guard against every imaginable risk. The law requires precautions only against risks that are reasonably likely to occur. A mere foreseeable possibility is not enough if, in practice, the chance of harm is so slight that a reasonable person would treat it as negligible. The court therefore asks not simply whether harm was possible, but whether the risk was sufficiently likely to call for preventive action.
(ii) Seriousness of the potential harm
The standard of care also depends on the gravity of the possible consequences. Even where the likelihood of harm is relatively low, greater precautions may be required if the potential harm would be especially serious. This is particularly so where the defendant knows that the plaintiff is unusually vulnerable. The law therefore weighs not only the probability of injury, but also the extent of the damage that might result if the risk materialises.
(iii) Cost and practicality of precautions
In deciding whether the defendant fell below the standard of care, the courts balance the risk against the burden of avoiding it. If a precaution is simple, inexpensive, and easy to implement, a failure to take it is more likely to be negligent. By contrast, where the proposed precaution would be very costly, impractical, or disproportionate to the level of risk, the defendant may not be in breach. This is often illustrated by the “Learned Hand formula”, where breach occurs if the cost of precautions (B) is less than the probability of harm (P) multiplied by the seriousness of the injury (L). However, the courts do not apply this mechanically. It remains a broad judgment of reasonableness in all the circumstances.
(iv) Social value or utility of the activity
The court may also consider the social value of the defendant’s conduct. Activities carried out to save life, prevent serious injury, or serve some important public purpose may justify the taking of greater risks than would be acceptable in ordinary commercial or recreational contexts. However, social utility is not a complete defence. The court will still ask whether the particular risk created was justified by the value of the activity in question. A generally worthwhile activity does not excuse unnecessary or avoidable dangers.
(v) Common practice and regulations
Compliance with common practice may be evidence that the defendant acted reasonably, but it is not conclusive. A practice does not cease to be negligent merely because it is widely followed. The court ultimately decides whether the practice itself meets the required standard of care. An important qualification applies in professional negligence: where the defendant is exercising a special skill, adherence to a practice accepted as proper by a responsible body of professional opinion will usually indicate no breach, provided that opinion is capable of withstanding logical scrutiny. In addition, breach of a relevant rule or a criminal conviction does not automatically establish negligence, but it may amount to prima facie evidence supporting the plaintiff’s case.
Personal characteristics of the defendant
As a general rule, the objective standard does not vary according to the defendant’s personal idiosyncrasies, lack of skill, or “incompetent best”. The law asks what a reasonably competent person in that role would have done. However, the court must account for specific knowledge the defendant possessed regarding a particular risk or the plaintiff’s vulnerability, such as knowing an employee has only one good eye. The question then becomes what a reasonable person, possessing that knowledge, would have done by way of precaution.
(i) Inexperience
A learner driver is held to the same standard as an experienced, skilled, and careful driver. Similarly, a junior doctor is judged by the standard of a competent professional occupying that specific post, making no allowance for the fact that he is learning “on the job”.
(ii) Exceptions for children
Children are a separate class. They must meet the standard of an ordinarily prudent child of the same age and maturity.
For more information, please refer to “Children”.
(iii) Physical or mental illness
Although personal weaknesses are usually disregarded, the courts may adjust the standard where the defendant was suddenly incapacitated by an unknown condition and had no reason to be aware of the danger. For example, a driver who suffers an unforeseen hypoglycaemic episode may not be negligent if he was genuinely unaware of his unfitness to drive. By contrast, if a defendant has any awareness of being unwell and continues to drive, he remains liable under the standard of a reasonable driver.
(iv) Professionals and people with special skills
Where the defendant possesses or claims special skill, the standard is adjusted accordingly. A professional is not judged by the standard of an ordinary layperson, but by the standard of a reasonably competent member of that profession or calling. He is not negligent if he acted in a way supported by a “responsible body of professional opinion”, even if other experts disagree. However, the court can reject an expert’s opinion if it is not logically supported.
For more information, please refer to “Professional liability”.
