What happened
The plaintiff, Mr Malec, worked as a labourer in the defendant's meatworks between October 1972 and April 1980. In the course of that employment he contracted acute brucellosis, a disease acquired from animals, as a result of the defendant's negligence. One recognised sequela of brucellosis is depressive illness; another is an organic condition producing a degenerative-like spinal state. The trial judge (Carter J.) found that the plaintiff had contracted acute brucellosis between 1975 and 1977, that the condition was no longer present by June 1983, and that a neurotic illness diagnosed in 1979 had been precipitated by the brucellosis. However, his Honour was not satisfied that the plaintiff's cervical and lumbar spinal symptoms, present since at least 1982, were caused by the brucellosis. He further found that the neurotic condition from which the plaintiff suffered at trial in September 1987 was probably not related to the 1975–1977 brucellosis episode. That last finding was overturned by the Full Court of the Supreme Court of Queensland, which held unanimously that the plaintiff's neurotic condition at trial was caused by depression induced by the acute brucellosis.
The majority of the Full Court (Matthews and Ambrose JJ.) went on to hold that, by reason of the plaintiff's personality, it was likely that the development of symptoms from his deteriorating back condition would have produced a similar neurotic condition even if he had never contracted brucellosis. They expressed the view that, quite apart from brucellosis, by age forty-four the plaintiff would have become unemployable as a result of his back condition and would have developed a similar neurotic condition. At trial the plaintiff was forty-nine. Accordingly the majority limited damages for economic loss to the period ending in May 1982. They awarded $15,000 for pain and suffering, apportioning $12,000 to the pre-trial period and only $3,000 post-trial, and refused any award for the care and attention provided by the plaintiff's wife on the basis that, by mid-1982, any such care was unrelated to the brucellosis or its attendant neurosis.
Carter J., dissenting in the Full Court, would have assessed damages on the footing that the neurotic decompensation caused by brucellosis would continue and would render the plaintiff unemployable for the foreseeable future. His Honour considered that two discounting factors had to be taken into account: first, that some symptoms were referable to the unrelated spinal condition, and second, that the plaintiff's personality made him vulnerable to psychiatric disability from other events. Carter J. would also have awarded $70,000 for gratuitous care under the principle in Griffiths v Kerkemeyer.
The High Court (Brennan, Deane, Dawson, Gaudron and McHugh JJ.) allowed the plaintiff's appeal. The joint judgment of Deane, Gaudron and McHugh JJ. (with which Brennan and Dawson JJ. agreed subject to brief observations) held that the majority had erred in refusing any damages for economic loss after May 1982, in their approach to pain and suffering, and in denying damages for care. The Court set aside the Full Court's award of $36,928.47 and remitted the assessment to the Master to be carried out in accordance with the High Court's reasons, the evidence, and (subject to those reasons) Carter J.'s findings, while treating the majority's view that the back condition would probably have rendered the plaintiff unemployable from 1982 as guidance on the relevant chances. The costs limitation imposed by the trial judge was also removed.
Why the court decided this way
The High Court's reasoning rests on a fundamental distinction between the treatment of past facts and the treatment of future or hypothetical events. Once liability is established, a court ascertains whether an event has occurred on the balance of probabilities. If it is more probable than not that the event occurred, the court treats it as certain; if less probable, it treats it as not having occurred. This produces an all-or-nothing outcome for historical facts. By contrast, when the court must consider what would have occurred but for the tort, or what might yet occur, it cannot apply the same binary approach. Questions of future or hypothetical effect of injury are not susceptible of scientific proof. The law therefore takes account of such events only in terms of the degree of probability that they would have occurred or might occur.
Deane, Gaudron and McHugh JJ. explained that the probability may range from 99.9 per cent to 0.1 per cent. Unless the chance is so low as to be merely speculative (say less than 1 per cent) or so high as to be practically certain (say over 99 per cent), the court must reflect that chance in the damages awarded. This principle is drawn directly from Lord Diplock's speech in Mallett v McMonagle and is reinforced by Davies v Taylor and McIntosh v Williams. The same method applies whether the hypothetical event is said to lie in the past or the future.
Applied to the facts, the plaintiff had established that his neurotic condition at trial, which rendered him unemployable, was the result of the brucellosis. There was little or no chance of recovery. Subject only to ordinary vicissitudes, he was prima facie entitled to compensation for the near-certainty of lifelong unemployability caused by the defendant's negligence. The majority in the Full Court had found it "likely" (i.e., more probable than not) that, independently of the brucellosis, the plaintiff's back condition would have rendered him unemployable by May 1982 and would have produced a similar neurotic condition. That finding was treated by the High Court as open on the evidence and was to be accepted by the Master as guidance. However, it was impossible to say the chance was 100 per cent. Therefore the damages otherwise recoverable had to be reduced to reflect the chance that the back condition would have produced the same consequences. The majority's error was to treat that likelihood as justifying a complete cut-off of economic loss after May 1982 and a virtual denial of damages for ongoing pain and care. That was an impermissible all-or-nothing application of the balance of probabilities to a hypothetical.
Brennan and Dawson JJ. emphasised the same distinction. The fact that the plaintiff had not worked for some time before trial was a matter of history to be decided on the balance of probabilities. Earning capacity, however, could only be assessed on the false hypothesis that the tort had not occurred. That assessment necessarily involves speculation and an evaluation of possibilities. Their Honours cautioned against expressing such evaluations as percentages where it could be avoided, and against using the word "probability" for minimal possibilities, but agreed that the majority had misconceived the process by treating the hypothetical back-condition scenario as though it were a past fact already proven on the balance of probabilities.
The High Court further held that the chance that the back condition and consequent unemployability would have precipitated a similar neurotic condition was not overwhelming. The plaintiff had in fact developed neurosis only after suffering prolonged and severe symptoms from brucellosis. It could not be assumed that another event would necessarily have done the same. Moreover, where two probabilities are involved (the probability of unemployability from the back alone, and the probability that such unemployability would then cause neurosis), the combined chance decreases exponentially. The majority had therefore also erred in refusing Griffiths v Kerkemeyer damages for the wife's care and in their limited award for pain and suffering. Both heads had to be assessed on the basis that the neurotic condition was caused by the negligence, but discounted for the chance that unrelated factors would have produced similar consequences and similar care needs.
The disposition followed: the appeal was allowed, the inadequate award set aside, and the matter remitted to the Master with clear directions on the correct methodology.
Before and after state of the law
Before Malec v JC Hutton Pty Ltd the law on damages for personal injury already contained the seeds of the probabilistic approach. Mallett v McMonagle had made clear that the court must estimate chances rather than decide what "would have" happened on the balance of probabilities. Australian courts had applied that reasoning in cases such as Davies v Taylor (loss of dependency) and McIntosh v Williams (lost opportunity). Nevertheless, lower courts continued to slip into all-or-nothing reasoning when confronted with pre-existing degenerative conditions or vulnerabilities that might have produced the same outcome. The Full Court majority's judgment in the present case was a textbook example: once it was "likely" that the back condition would have caused identical incapacity and neurosis, damages were cut off at May 1982.
Malec crystallised and reinforced the distinction between past facts and hypotheticals. It made explicit that the evaluation applies equally to hypothetical past events ("what would have happened if the tort had not occurred") and to future possibilities. It emphasised that a chance between 1 per cent and 99 per cent must be reflected in the award; there is no room for a 51 per cent threshold that produces a binary cut-off. The decision also illustrated the multiplicative nature of probabilities when more than one hypothetical step is required. After Malec, Australian courts have been required to approach "crumbling skull" or "eggshell personality" cases by assessing the chance that the plaintiff would have suffered the same harm from independent causes and discounting the damages accordingly, rather than denying recovery altogether once the chance exceeds 50 per cent.
The principle has become a cornerstone of personal injury litigation. It is routinely cited for the proposition that damages are assessed on the basis of "loss of a chance" where the tort has destroyed or diminished a valuable opportunity, and for the symmetrical treatment of past hypotheticals and future contingencies. The addendum delivered by the Court on 26 June 1990, removing the trial judge's costs limitation once the basis for restricting damages was overturned, further underscored that costs orders must follow the corrected assessment of the plaintiff's entitlement.
Key passages with plain-English translation
The joint judgment contains several passages that have become canonical. The opening of the section "Assessing Damages for Future or Potential Events" states:
"When liability has been established and a common law court has to assess damages, its approach to events that allegedly would have occurred, but cannot now occur, or that allegedly might occur, is different from its approach to events which allegedly have occurred. A common law court determines on the balance of probabilities whether an event has occurred. If the probability of the event having occurred is greater than it not having occurred, the occurrence of the event is treated as certain ... But in the case of an event which it is alleged would or would not have occurred, or might or might not yet occur, the approach of the court is different. ... If the law is to take account of future or hypothetical events in assessing damages, it can only do so in terms of the degree of probability of those events occurring. ... Unless the chance is so low as to be regarded as speculative — say less than 1 per cent — or so high as to be practically certain — say over 99 per cent — the court will take that chance into account in assessing the damages."
Plain-English translation: Past events are decided yes-or-no on a 51/49 basis. Future or "what-if" events are decided by percentage likelihood, and the compensation is scaled up or down to match that percentage. A 49 per cent chance is not ignored; a 75 per cent chance does not give full recovery.
Later, when dealing with the Full Court's error, the judgment observes:
"On the evidence, it is impossible to conclude that it is 100 per cent certain that the plaintiff's back condition would have rendered him unemployable if he had not contracted brucellosis. So, on the majority's finding, the reduction in his damages for loss of earning capacity would be somewhere between 51 per cent and 99 per cent. But whatever the precise chance of the plaintiff's back condition totally or partially reducing his earning capacity, the majority in the Full Court erred in refusing to award him any damages for economic loss suffered after May 1982."
Plain-English translation: Even if the judge thinks there is a 70 per cent chance the bad back would have caused the same problems anyway, the plaintiff still gets 30 per cent of the full value of his lost earnings after 1982, not zero.
The Court also explained the mathematics of combined probabilities:
"When those probabilities are combined, the chance that the plaintiff would develop a neurotic condition decreases exponentially. If, for example, and only by way of illustration, there was a 75 per cent probability of his becoming unemployable by reason of his back condition even if he had not contracted brucellosis and a 75 per cent chance that that unemployability would have caused a similar neurotic condition, there was only a 56.25 per cent chance (75 per cent x 75 per cent) that, if he had not contracted brucellosis, he would have developed a similar neurotic condition."
Plain-English translation: You do not simply take the higher of two chances; you multiply them. A 75 per cent chance of unemployability times a 75 per cent chance that unemployability would cause neurosis equals only a 56.25 per cent chance overall. That is the discount to apply.
Brennan and Dawson JJ. added a practical note:
"In assessing the plaintiff's earning capacity in the present case, what had to be evaluated was the prospect that the deteriorating back condition would have precluded him from engaging in gainful employment had he not contracted brucellosis. An evaluation of that prospect had to be made. To make a finding on the balance of probabilities as though the prospect were something that had occurred in the past was to misconceive the process of evaluation."
Plain-English translation: The fact that the man had not worked recently is one thing; what he would have earned if the brucellosis had never happened is a different, speculative question that cannot be answered with a straight "more likely than not" finding.
What fact patterns trigger this precedent
Malec is engaged whenever a defendant argues that the plaintiff's current condition or incapacity would have arisen in any event from a pre-existing degenerative condition, a vulnerable personality, or some other independent cause. Typical triggers include:
- A plaintiff with a pre-existing but asymptomatic spinal degeneration who develops symptoms after a tortious incident and the defendant says the symptoms would have appeared anyway.
- A plaintiff with a psychiatric history or fragile personality who suffers a tortiously induced psychiatric injury and the defendant contends that some other life event would probably have triggered equivalent decompensation.
- Claims for future economic loss where the plaintiff's work history or medical records suggest that retirement, redundancy or other non-tortious factors would have ended earning capacity at or about the same time as the injury.
- Griffiths v Kerkemeyer claims for gratuitous care where the carer’s services might have been required in any event because of unrelated ageing or disease.
- Any case in which the evidence supports a finding that it is "likely" (more than 50 per cent) but not certain that the same harm would have materialised independently.
The precedent does not apply to the determination of whether the defendant’s negligence in fact caused the injury in the first place; that remains a balance-of-probabilities question. It applies only once causation is established and the court moves to quantify the extent of the loss that is attributable to the tort as opposed to independent factors.
How later courts have treated it
Malec has been followed and applied consistently by Australian courts at every level. In Sellars v Adelaide Petroleum NL the High Court itself cited Malec for the proposition that damages for loss of a commercial opportunity are assessed by reference to the degree of probability of the opportunity being realised. In Commonwealth v Amann Aviation Pty Ltd the principle was extended to contractual damages for lost profits. State courts routinely cite Malec in personal injury appeals when adjusting awards for "crumbling skull" plaintiffs. For example, in Watts v Rake (post-Malec applications) and subsequent decisions such as Purcell v Watson and Government Insurance Office v Rosniak, courts have discounted damages by explicit percentages to reflect the chance that unrelated conditions would have produced the same incapacity.
The decision has been distinguished where the evidence shows the independent cause would have produced the identical harm with virtual certainty (the 99 per cent case), or where the chance is truly speculative. It has not been overruled. Later courts have noted Brennan and Dawson JJ.'s caution against mechanical percentage discounts, preferring where possible to arrive at a single discounted figure rather than stating "we award $500,000 less 35 per cent". Nevertheless, explicit percentage reasoning remains common in trial judgments and is rarely disturbed on appeal if the evidentiary basis is sound. The multiplicative approach to successive probabilities has been applied in cases involving both economic loss and non-economic loss, and in claims for gratuitous services.
Still-open questions
Although Malec is now settled doctrine, several practical questions remain. First, how low a probability must be before it is regarded as "speculative" and ignored? The joint judgment gives 1 per cent as an illustrative threshold, but later cases have struggled with whether 5 per cent or 10 per cent should be disregarded. Second, the precise interaction between Malec discounting and the statutory caps and thresholds introduced by civil liability legislation in most Australian jurisdictions has not been fully worked through. Some courts have applied Malec discounts before applying statutory maximums for non-economic loss; others have done so afterwards. The High Court has not yet authoritatively resolved the sequence.
Third, the extent to which a Malec discount can be applied to general damages for pain and suffering remains somewhat opaque. The joint judgment clearly contemplates such a discount, yet some trial judges have been reluctant to reduce an award for past pain actually suffered on the footing that the plaintiff might have suffered equivalent pain from another cause in the future. Fourth, the evidentiary standard required to establish the "chance" of a hypothetical event is not spelled out. Must there be medical evidence capable of quantification, or is a judicial impression based on lay evidence sufficient?
Finally, Brennan and Dawson JJ.'s observation that damages "defy precise calculation" and their preference for avoiding percentage language sits in tension with the modern tendency toward transparent, arithmetical reasoning in judgments. Whether appellate courts will increasingly insist on global rather than percentage-based assessments in complex hypothetical cases is still an open question. Until the High Court revisits the issue, practitioners must navigate the tension between the need for intellectual honesty in explaining discounts and the undoubted truth that hypothetical evaluations are not capable of mathematical precision. These unresolved edges ensure that Malec continues to generate sophisticated argument in high-value personal injury litigation more than three decades after it was decided.