Tort Law - Negligence
A question to be asked in every instance is whether the harm alleged was actually caused by the act or omission of the defendant, or whether there was some extraneous factor involved, without which the harm would not have resulted. Extraneous factors can include another person’s action or omission, or some non-human cause. The classical test of causation was the “but for” test where it is asked “but for the defendant’s act, would the allegedly resultant damage have occurred?” This test works well in situations such as where a plaintiff has a pre-existing medical condition made worse by the defendant. But it has been shown inadequate in instances where two parties act concurrently to produce the risk. (Either two potential defendants or a plaintiff acting in contributory negligence). One such example is March v Stramare. A truck was parked late early in the morning in the middle of a six lane road in front of a wholesale produce market. This was the most convenient position and was a normal practice. The plaintiff, driving drunk and at excessive speed, collided with the truck. The negligence was found to be shared between defendant and plaintiff, with the court arriving at percentages of blame. Thus the plaintiff’s award in damages was reduced proportionally to his proportion of blame.
This is a leading case. Prior to it the action of the plaintiff would be deemed to be a novus actus interveniens (new intervening act) which would have completely broken the causal chain and defeated his claim completely. An important issue was that the defendant had created the situation in which the plaintiff’s actions were able to generate the harm, for though he was drunk and speeding, it is plausible the plaintiff could otherwise have arrived home safely.
The Eggshell Skull Rule
The eggshell skull rule is commonly phased, ‘you take the plaintiff as you find them.’ The name is illustrative of when the rule comes into play. If the plaintiff is in an accident which would cause a minor injury to most people, and due to inherent weakness incurs a serious injury, they still deserve compensation for the injury they actually suffered. So, a person who is physically or financially vulnerable to harm is treated the same as any other person, and their pre-existing vulnerability injury is not taken against them when considering the causation of their injury. This rule is only inapplicable where the resulting harm is actually symptomatic of a pre-existing condition.
This could incorrectly be viewed as an issue of foreseeability; however it is actually a matter of causation. A defendant will wish to draw a distinction between the harm actually brought about by their negligence, and that which was brought about by another cause such as an illness, or impecuniousness (leading to debt or business closure, for example). Under the minimum actionable harm rule emerging from the Ipp Review, one may have no justification in terms of potential liability to exercise a duty of care in relation to a lot of minor concerns. Nevertheless, the possibility that a person of special vulnerability may happen upon the scene, can turn a minor safety concern into something that requires serious attention.
A person placing themselves in the way of danger to stop or prevent a dangerous situation, or rescue others who are in danger, might be said to be partly to blame of any injuries sustained. They could be said to have voluntarily assumed risk (see Defences, below), or to have introduced a novus actus interveniens (new intervening act) in the form of their own decision to act. However courts take the view that anyone placing themselves in danger specifically because of the result of the defendant’s negligence is not caught by these rules. In Haynes v Harwood a two horse van was left unattended and the horses bolted. A policeman intervened to bring the horses under control and was injured in doing so. The policeman’s action was seen not to be a new intervening act as this was a thing likely to happen under the circumstances. Voluntarily assumption of risk was ruled not be relevant when facing a risk created by the defendant’s misconduct.
A significant issue in this case for civilian law enforcers is found in the statement that the fact that it was a policeman involved made it all the more to be expected that he would step in to manage the situation. Therefore the existence of a specific duty to take action makes it easier for a person to sue for damages if injured in the process of acting. Such duties tend to be incumbent upon security guards and emergency services personnel. While employers emphasise personal safety, the rule created in Haynes remains current law.
 March v E & MH Stramare Pty Ltd (1991) 171 CLR 506.
 Haynes v Harwood  2 KB 240.