Breach of Duty and Causation

Breach of duty in negligence liability may be found to exist where the defendant fails to meet the standard of care required by law. Once it has been established that the defendant owed the claimant a duty of care, the claimant must also demonstrate that the defendant was in breach of duty. The test of breach of duty is generally objective. The abstract reasonable person is put into the shoes of the defendant, who is expected to have the same general knowledge and understanding of risks (say, that icy roads are slippery or that children may get up to mischief) as the reasonable person. The actual defendant may be more stupid or more ignorant, or may be cleverer or more knowledgeable, but is still judged by this abstract impersonal standard.
Whether the defendant in question is judged as a reasonable average man or a reasonable skilled man, the law applies an objective test of reasonableness. This means that any characteristics of the defendant or any characteristics shared among a particular class of defendants which might affect their capacity to carry out a task to a reasonable standard, are not taken into account when determining whether the defendant has fallen below the standard of care.
Most of the difficult reported cases, however, involve defendants with special skills or qualifications. It would be silly to ask whether a reasonable ‘person’ would have removed the appendix or designed the building in the same way as the actual surgeon or architect who is being sued. For this we resort to the Bolam Test. In cases of medical negligence, the determination of standard of care is determined by medical judgment. A child is not expected to meet the standard of a reasonable adult, but will be judged by the standard of a reasonable child of the same age. In later case law we also see that Bolam Test has extended its ambit to include other professions as well.
Once a breach of duty has been established, the claimant must then also show that the breach has resulted in injury or damage (the causation issue). To demonstrate causation in tort law, the claimant must establish that the loss they have suffered was caused by the defendant. In most cases a simple application of the 'but for' test will resolve the question of causation in tort law. Ie 'but for' the defendant's actions, would the claimant have suffered the loss? If yes, the defendant is not liable. If no, the defendant is liable. Causation is relevant to all torts in which proof of damage is essential.
The ‘but for’ test is generally a good test as to whether the breach of duty was the cause of the harm, but it has limitations. Problems in the application of the ‘but for’ test arise when the answer to the question leads to an unjust or contradictory result, such as, for example, where the damage could have been caused by the fault of more than one defendant. This situation arose in the Canadian case of Cook v Lewis [1951] SCR 830, when two hunters negligently fired their guns in the direction of the claimant. One bullet hit him, but it was not established which gun had fired that bullet. In the absence of the required proof, it was held that both defendants should be liable. Further problems with the ‘but for’ test can be contemplated in cases where there is material contribution to harm, or material increase in risks.
Where there is a new intervening act this may break the chain of causation removing liability from the defendant. The legal test applicable will depend upon whether the new act was that of a third party or an act of the claimant. Where the new act is of a third party, the test is whether the act was foreseeable. If the act of the third party was foreseeable, the defendant remains liable and the chain of causation remains intact. If the act of a third party is not foreseeable this will break the chain of causation and the defendant is not liable for the actions of the third party. Where the new intervening act is that of the claimant, the test is whether the claimant acted reasonably in the circumstances. If the claimant's actions are deemed reasonable the chain of causation remains intact and the defendant is liable for the actions of the claimant. If, however, the claimant's actions are unreasonable in the circumstances the chain of causation is broken and the defendant is not liable for the actions of the claimant.
Where the claimant submits the defendant's conduct lost them a chance of avoiding harm or injury as opposed to causing the harm or injury itself, the courts have been reluctant at imposing liability. This most commonly comes up in relation to medical negligence whereby a failure to diagnose a condition correctly may prevent the claimant from receiving vital treatment which may have saved their life or avoided a deterioration in their condition.