On 21 April 2010 the High Court handed down its decision in Gett v Tabet  HCA 12. The High Court concluded that the New South Wales Court of Appeal had made the correct decision when it found that the principle of loss of chance in medical negligence cases was a departure from conventional principles and was plainly wrong.
The appellant, Reema Tabet, suffered a significant brain injury after an alleged delay in diagnosis of a brain tumour. She claimed that had the respondent, Dr Gett, performed a CT scan on 13 January 1991, her brain tumour would have been diagnosed and treated thus avoiding the seizure on 14 January 1991 which caused a proportion of her brain damage.
The appellant alleged that, as a result of the failure to perform the CT scan, she was deprived of a chance of a better outcome.
The trial judge found that Dr Gett had breached his duty of care in not ordering an urgent CT scan on 13 January 1991. He concluded that 25% of the appellant’s brain damage was caused by her neurological deterioration on 14 January 1991. The balance was caused by other factors including the effect of the surgery and subsequent treatment (radiation and chemotherapy).
On the issue of causation, the trial judge was unable to find on the balance of probabilities that Dr Gett’s breach of duty caused or contributed to her brain damage. Following a case of Rufo v Hoskings  NSWCA 391 he found that the appellant had lost a chance of a better outcome, which he assessed at 40%.
Dr Gett appealed to the New South Wales Court of Appeal which unanimously decided that the trial judge’s decision was incorrect. The court was of the opinion that the principle of loss of chance in medical negligence cases was “a departure from conventional principles and in our respectful view, is plainly wrong.”
In the opinion of the Court of Appeal, to admit recovery for the claim for loss of chance involved a proposition which would revolutionise proof of causation of injury and that it should be for the High Court to make those decisions.
The High Court
The High Court unanimously dismissed Reema Tabet’s appeal, with costs. However Heydon J in his decision concluded that, as the evidence did not support that there was any chance of the appellant avoiding brain damage, the question as to whether the appellant was deprived of a loss of chance of a better outcome was a hypothetical one which he was not called upon to decide in this case.
Of the remaining judges, Gummow ACJ, Hayne, Crennan, Kiefel and Bell JJ in summary found:
- An action in negligence lies only if damage is sustained. Damage is an essential ingredient in an action for negligence; it is the gist of the action.
- The traditional approach in personal injury cases represents the striking of a balance between the competing interests of the parties. The substitution of the loss of a chance as the actionable damage represents a shift in that balance towards the claimant. Any potential benefit of such an approach had to be weighed against, for example, the prospect of “defensive medicine”.
- The loss of a chance diverts attention from the proper connection between fault and damage. It is artificial and breaks the causal link.
- The argument that there should be compensation when breach of duty is proved simply denies proof of damage as necessary to an action in negligence.
- The difficulty for the appellant was that there was no evidence as to what harm might have been caused by the delay. It could not be said that “but for” the delay she would not have suffered brain damage.
- The appellant was unable to prove on the balance of probabilities, that had she received earlier treatment, the brain damage would not have occurred. A claim like this could only succeed if the standard of proof were lowered, which would require a fundamental change to the law of negligence. It would involve holding the respondent liable for damage which he almost certainly did not cause.
The High Court has not abolished loss of chance claims in Australia. However, for such claims to succeed in the future, the High Court has re-affirmed that the plaintiff must prove that, but for the alleged negligence, he or she had better than 50% chance of a better outcome.
The decision is also consistent with the definition of harm in the Civil Liability Act 2003 (Qld), which does not extend to the “risk” of injury, and also of the requirement in the Act that plaintiff always bears the onus of proof, on the balance of probabilities, of any fact relevant to the issue of causation.