The High Court of Australia has recently closed a door on plaintiffs in medical negligence claiming for ‘loss of a chance.’ In doing so it refused, unanimously, to extend the law of negligence, to modify the ‘all or nothing’ rule, and to reformulate the concept of ‘damage’ in tort. The question raised by the appeal is ‘a question which has divided courts and commentators throughout the common law world.’ Thus the Court’s decision is most significant.
What is Loss of a Chance?
In order to understand the central tension in Tabet (whether ‘loss of a chance’ is compensable harm), it is necessary to have some understanding of the facts of the case and relate these facts to the fundamental principles of the tort of negligence and actions in breach of contract.
The appellant, Ms Tabet, suffered irreversible brain damage, partly arising from the conduct of the respondent, Dr Gett, partly as a result of a tumour, and partly from other non-negligent medical treatment. The appellant alleged that Dr Gett was negligent in failing to undertake a CT scan, which was ultimately conducted on 14 January 1991, on either 13 January or 11 January, and had the CT scan been conducted without this delay, the she would have had a ‘better medical outcome.’
The trial judge (and the Court of Appeal) held that the discovery of the tumour upon the administration of the CT scan on 13 January would not, on the balance of probabilities, have led to the appellant being treated in a way which would have avoided the seizure and the deterioration of her condition. Nevertheless, Studdert J held that the appellant had lost a chance of a better medical outcome, assessed this chance at 40% and awarded damages accordingly. This decision was reversed by the Court of Appeal which was in turn upheld by the High Court.
In confining the law of medical negligence, The High Court made detailed reference to the state of authority and in particular to the recent House of Lords decision of Gregg v Scott. Similarly, Gregg was concerned with a delay in medical treatment which, while not causative of any loss on the balance of probabilities, reduced the plaintiff’s chances of being ‘cured’ (of cancer) from roughly 42% to 25%. The House of Lords by a narrow 3 to 2 majority refused, as did the High Court, to recognise this reduced chance as compensable harm.
While recognising similar principles in making their decisions, their Lordships and the members of the High Court emphasised different policy considerations for refusing recovery. Nevertheless, in the context of this discussion on the differences between tort and contract law and the impact of this decision, there are two noteworthy points.
Firstly, it is of fundamental significance that the plaintiff in Tabet did not pursue a claim in breach of contract. This allowed the High Court to confine its analysis to a consideration of the principles which relate specifically to the law of negligence. Had the claim been framed in the alternative, the result could perhaps have been much different.
Secondly, and as a matter of fact, if the alleged negligence in these cases had have caused a loss of a chance of greater than 50%, then it would have, on the balance of probabilities, been causative of the harm suffered and therefore been compensable. That is, it would cease to be merely a loss of a chance – it would be actual ‘damage.’ Any lost chance less than 50% (as was the case in Tabet and Gregg), however is not proven on the balance of probabilities and is therefore not compensable. Whether this ‘all or nothing’ approach is correct in principle is indeed at the very heart of the issue of this debate in the context of tort law.
All or Nothing Rule
The combination of the burden of proof being on the plaintiff in negligence, the standard being the balance of probabilities, and damage being the gist of negligence all lead, as a matter of logic, to the ‘all or nothing rule’ of recovery in negligence. Put simply this is rule that says that once the defendant’s breach is found to be the legal cause of a plaintiff’s harm, the defendant is liable for the whole of the damage. Contrast this with the ‘loss of a chance’ view which would award plaintiffs who are not able to show on the balance of probabilities that the breach was causative of the entire harm, but who can show that there was a lost opportunity (in these instances damages are reduced in proportion to this lost chance).
Supporters of the loss of a chance view argue that loss of a chance is indeed something valuable in and of itself. Indeed the law recognises this in commercial contexts. Further the distinction between an outcome and an opportunity (which is fundamental to the defenders of the all or nothing view) is theoretically unstable.27 That is, an opportunity can always be described as an outcome; for example Ms Tabet could allege that the defendant’s negligence indeed deprived her of a particular desirable outcome, namely of being in the position of having a 15% chance of avoiding the brain tumour. Finally, even in the words of Gummow ACJ, there is a ‘rough justice’ in totally compensating the plaintiff who has lost a 51% chance but denying totally compensation to the plaintiff who has lost a 49% chance.
Defenders of the ‘all or nothing’ view point to the need to protect the coherence and integrity of negligence law. As Lord Hoffman puts it, in negligence, ‘everything has a determinate cause, even if we do not know what it is… the law deals with lack of knowledge by the concept of the burden of proof.’ Altering the ‘all or nothing’ rule would involve revolutionising the standard of proof, turning compensating the probable into the mere possible. Doing so would make it much more favourable for the plaintiff; if loss of an outcome and loss of a chance of an outcome were retained as alternatives, then the plaintiff would almost always receive some compensation. In the words of Baroness Hale, it would be like ‘heads you lose everything, tails I win something.’ This is of course unless the law of negligence was redefined so that proportionate recovery ‘cut both ways’ insofar as those claimants with a better than even chance still only received a proportion of their claim. But this would represent ‘two steps forward and three steps back for the great majority of straightforward personal injury claims’, and of necessity ‘expert evidence would be far more complex than it is at present.’
Marc Testart, Barrister
MyLearnedFriends 
Posted on June 19, 2011
0