Strong v Woolworths Ltd [2012] HCA 5 (7 March 2012)

I refer to my previous posting and the judgment summary of the High Court by way of background and the facts.

This long awaited decision is of some importance because of its consideration of causation under 5D of the Civil Liability Act 2002 (NSW) (“Act”). The analogue Queensland provision is s.11 of the Civil Liability Act 2003 (Qld) and comparatively s.305D of the Workers’ Compensation and Rehabilitation Act 2003 (Qld) applies for post 01/07/2010 injuries. I refer you to my earlier posting with respect to the emerging discussion of causation under these analogue provisions.  


Causation under the CLA


Part 1A of the CLA applies to any claim for damages for harm resulting from negligence, regardless of whether the claim is brought in tort, in contract, under statute or otherwise[12]. “Negligence”, for the purpose of Pt 1A, means the failure to exercise reasonable care and skill[13]. Section 5E provides that, in determining liability for negligence, the plaintiff always bears the onus of proving, on the balance of probabilities, any fact relevant to the issue of causation. As earlier noted, the principles governing the determination of causation are set out in s 5D. Relevantly, that provision states:

“(1) A determination that negligence caused particular harm comprises the following elements:
(a) that the negligence was a necessary condition of the occurrence of the harm (factual causation), and
(b) that it is appropriate for the scope of the negligent person’s liability to extend to the harm so caused (scope of liability).
(2) In determining in an exceptional case, in accordance with established principles, whether negligence that cannot be established as a necessary condition of the occurrence of harm should be accepted as establishing factual causation, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party.”


The determination of factual causation under s 5D(1)(a) is a statutory statement of the “but for” test of causation[14]: the plaintiff would not have suffered the particular harm but for the defendant’s negligence. While the value of that test as a negative criterion of causation has long been recognised[15], two kinds of limitations have been identified. First, it produces anomalous results in particular cases, exemplified by those in which there is more than one sufficient condition of the plaintiff’s harm. Secondly, it does not address the policy considerations that are bound up in the attribution of legal responsibility for harm[16].



Under the statute, factual causation requires proof that the defendant’s negligence was a necessary condition of the occurrence of the particular harm[21]. A necessary condition is a condition that must be present for the occurrence of the harm. However, there may be more than one set of conditions necessary for the occurrence of particular harm and it follows that a defendant’s negligent act or omission which is necessary to complete a set of conditions that are jointly sufficient to account for the occurrence of the harm will meet the test of factual causation within s 5D(1)(a)[22]. In such a case, the defendant’s conduct may be described as contributing to the occurrence of the harm. This is pertinent to the appellant’s attack on the Court of Appeal’s reasons, which is directed to par 48 of the judgment:

“Now, apart from the ‘exceptional case that section 5D(2) recognises, section 5D(1) sets out what must be established to conclude that negligence caused particular harm. That emerges from the words ‘comprises the following elements‘ in the chapeau to section 5D(1).Material contribution‘, and notions of increase in risk, have no role to play in section 5D(1). It well may be that many actions or omissions that the common law would have recognised as making a material contribution to the harm that a plaintiff suffered will fall within section 5D(1), but that does not alter the fact that the concepts of material contribution and increase in risk have no role to play in deciding whether section 5D(1) is satisfied in any particular case.” (emphasis in original)


Section 5D(2) makes special provision for cases in which factual causation cannot be established on a “but for” analysis. The provision permits a finding of causation in exceptional cases, notwithstanding that the defendant’s negligence cannot be established as a necessary condition of the occurrence of the harm. Whether negligent conduct resulting in a material increase in risk may be said to admit of proof of causation in accordance with established principles under the common law of Australia has not been considered by this Court[37]. Negligent conduct that materially contributes to the plaintiff’s harm but which cannot be shown to have been a necessary condition of its occurrence may, in accordance with established principles[38], be accepted as establishing factual causation, subject to the normative considerations to which s 5D(2) requires that attention be directed.


The authors of the Ipp Report and Allsop P in Zanner v Zanner assume that cases exemplified by the decision in Bonnington Castings would not meet the test of factual causation under s 5D(1)(a). However, whether that is so would depend upon the scientific or medical evidence in the particular case, a point illustrated by the decision in Amaca Pty Ltd v Booth with respect to proof of causation under the common law[39]. In some cases, although the relative contribution of two or more factors to the particular harm cannot be determined, it may be that each factor was part of a set of conditions necessary to the occurrence of that harm.


As earlier noted, the limitations of the “but for” analysis of factual causation include cases in which there is more than one sufficient condition for the occurrence of the plaintiff’s injury. At common law, each sufficient condition may be treated as an independent cause of the plaintiff’s injury[40]. The Ipp Report noted the conceptual difficulty of accommodating cases of this description within a “but for” analysis, but made no recommendation because the common law rules for resolving cases of “causal over-determination” were generally considered to be satisfactory and fair[41]. How such cases are accommodated under the scheme of s 5D does not call for present consideration.


Correctly understood, there is no conflict between the Court of Appeal’s analysis of s 5D in this proceeding and Allsop P’s analysis of the provision in Zanner v Zanner. The Court of Appeal correctly held that causation is to be determined by reference to the statutory test. Contrary to the appellant’s submission, the Court of Appeal said nothing about how the application of that test might lead to an outcome that differed from the outcome that would have been reached by the application of the common law. The causation issue presented by the appellant’s claim has nothing to do with concepts of material contribution to harm, material increase in risk of harm, or any of the difficulties discussed by the text writers in the context of the limitations of a “but for” analysis of factual causation[42].


The Court of Appeal, in approaching the determination of causation under the statute, accepted that Woolworths’ negligent failure to implement a system of periodic inspection might be shown to have been a necessary condition of the appellant’s harm by the process of probabilistic reasoning adopted in Shoeys Pty Ltd v Allan[43]. In issue in the appeal is whether the Court of Appeal was right to conclude that it was not open on the evidence to apply that reasoning in this case.



The appellant was required to prove on the balance of probabilities that Woolworths’ negligence was a necessary condition of her harm. Woolworths’ negligence lay in its failure to employ a system for the periodic inspection and cleaning of the sidewalk sales area. Proof of the causal link between an omission and an occurrence requires consideration of the probable course of events had the omission not occurred. Here, the appellant was required to prove that, had a system of periodic inspection and cleaning of the sidewalk sales area been employed on the day of her fall, it is likely that the chip would have been detected and removed before she approached the entrance to Big W.


The sidewalk sales area was not inspected in the four and a half hours between the time when the area was set up for the day’s trading and the time of the appellant’s fall. There was no dispute that, had the area been inspected, the chip would have been detected and removed. The Court of Appeal observed that the chip was not lying at the very edge of the corridor, given that Ms Hurst was walking next to the appellant on her right, and noted the evidence that it was visible after the appellant’s fall.


Woolworths’ submission that it was necessary for the appellant to point to some evidence permitting an inference to be drawn concerning when the chip was deposited must be rejected. It was incumbent on the appellant to prove that it was more probable than not that Woolworths’ negligence was a necessary condition of her fall, but this onus could be discharged by consideration of the probabilities in circumstances in which the evidence did not establish when the chip was deposited. The point was illustrated by Hayne JA (as he then was) in Kocis v S E Dickens Pty Ltd[45]. His Honour posited a case in which reasonable care required the occupier of premises to carry out inspections at hourly intervals. Assume that no inspection is made on the day the plaintiff slips on a spill eight hours after the premises opened for trading. If there is no basis for concluding that the spill is likely to have occurred at some particular time rather than any other time, the probability is that that the spill occurred in the first seven hours of trading and not in the hour preceding the plaintiff’s fall[46]. As Hayne JA observed, a plaintiff must prove his or her case on the balance of probabilities and it is no answer to the question whether something has been demonstrated as being more probable than not to say that there is another possibility open[47]. The determination of the question turns on consideration of the probabilities.


The Court of Appeal rejected reasoning along these lines because it found that the deposit of the chip was not a hazard with an approximately equal likelihood of occurrence throughout the day[48]. That conclusion was based on a consideration of three circumstances. First, chips are a type of food some people eat for lunch[49]. Secondly, the appellant’s injury occurred at lunchtime[50]. Thirdly, a second cleaner was engaged for the three hours commencing at 11.00am, which was suggestive of an increased risk of things being dropped during that period[51]. These circumstances led the Court of Appeal to say[52]:

“[I]t cannot be concluded that it was more likely than not that if there had been dedicated cleaning of the area every 15 minutes, supplemented by employees who happened to see a danger either removing it themselves, or calling a cleaner, it is more likely than not that the [appellant] would not have fallen.”


The engagement of the second cleaner provides no support for a conclusion that the probabilities were against the chip being deposited before 12.15pm. At most, it is a circumstance that may provide some basis for an inference of increased traffic in the Centre in the period from 11.00am to 2.00pm. However, it would be necessary to take into account that the fulltime cleaner took her lunchbreak within this period, leaving one cleaner on duty during that time. Furthermore, the contract with the cleaning company did not provide for more frequent inspections of the common areas in the period from 11.00am to 2.00pm, which tends against any conclusion of an increased risk of the kind suggested by the Court of Appeal.


If one reckons lunchtime as between 12.00pm and 2.00pm, it is right to say that the probabilities are evenly balanced as to the deposit of the chip between 12.00pm and 12.15pm and 12.15pm and 12.30pm, provided the chip was acquired for consumption at lunch. The Court of Appeal said that there was no basis for concluding that it was more likely than not that the chip was not dropped “comparatively soon before the [appellant] slipped”[53]. It did not explain how it reasoned as to the likelihood that the chip was acquired at lunchtime. There was no basis for concluding that chips are more likely to be eaten for lunch than for breakfast or as a snack during the course of the morning. The inference was open that the chip was not present on the floor of the sidewalk sales area at the time the area was set up for the day’s trading. However, the conclusion that the chip had been deposited at a particular time rather than any other time on the day of the incident was speculation.


Reasonable care required inspection and removal of slipping hazards at intervals not greater than 20 minutes in the sidewalk sales area, which was adjacent to the food court. The evidence did not permit a finding of when, in the interval between 8.00am and 12.30pm, the chip came to be deposited in that area. In these circumstances, it was an error for the Court of Appeal to hold that it could not be concluded that the chip had been on the ground for long enough for it to be detected and removed by the operation of a reasonable cleaning system[54]. The probabilities favoured the conclusion that the chip was deposited in the longer period between 8.00am and 12.10pm and not the shorter period between 12.10pm and the time of the fall.


The appellant submitted that, despite the unsatisfactory nature of the trial, as the sole question raised by Woolworths on its appeal was whether causation was open, the appropriate order, should she succeed in this Court, was the restoration of her verdict. Woolworths did not submit to the contrary. In the circumstances, it is appropriate to make the orders that the appellant seeks.


Brisbane Barrister – David Cormack


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