- In order to succeed in establishing causation, a plaintiff must satisfy s 5D of the Civil Liability Act 2002 (NSW) (CLA) and demonstrate that a failure to take precautions caused the particular harm. Where a plaintiff cannot describe the precise mechanism of an incident, causation will be extremely difficult to establish.
- A plaintiff must provide evidence of a positive inference implying negligence, and must do more than give rise to conflicting inferences of an equal degree of probability.
- Pursuant to s 5E of the CLA, the onus of proof of causation lies at all times with the plaintiff.
The plaintiff resided on the lower level of a two story home. The home was owned by the plaintiff’s sister, who resided on the upper level. Access to the upper level of the home was gained by an internal staircase from the garage adjacent to the lower level. The sole means of access to the plaintiff’s lower level dwelling was through the garage. Two wooden stairs led from a tiled landing just above the level of the garage floor to a door. There was no balustrade on the right side of the stairs, which was open to the garage.
The plaintiff suffered severe injuries when she fell as she was negotiating stairs from the first floor dwelling to the garage and her head impacted with a parked car in the garage.
The plaintiff alleged that her sister, the defendant, as owner and occupier, was negligent for failing to erect a balustrade on the open side of the stairs leading to the garage.
Due to the head injuries the plaintiff sustained in the incident, she suffered amnesia and was unable to explain what had happened to cause her to fall. Contemporaneous medical records supported that the plaintiff had no recollection of how she fell after the incident. There were no witnesses. By the time of the hearing, the plaintiff’s medical condition had deteriorated and she was not able to give evidence. The plaintiff’s expert was also unable to conclude from which point on the stairs or the landing the plaintiff had fallen based on her final resting position on the floor.
At the hearing at first instance, the trial judge, Balla DCJ, was invited to draw an inference that given the severity of injuries, the plaintiff had fallen from the stairs and that her fall was caused by a defect in the stairs. However the trial judge found that it was equally as likely the plaintiff had fallen from the landing at the bottom of the steps and further, that mobility issues experienced by the plaintiff prior to the incident might have also caused her to fall.
The trial judge found that the plaintiff’s failure to identify the precise mechanism of the fall made it difficult to establish a cause of action under ss 5B and 5D of the CLA. The trial judge therefore had difficulty accepting that had there been a balustrade present, the fall would have been prevented. The plaintiff’s claim failed as the trial judge was not satisfied the fall was caused, or contributed to by a defect in the stairs.
The plaintiff appealed, alleging that the trial judge failed to give adequate reasons for deciding that the evidence gave rise to inferences of equal degrees of probability, misdirected herself as to the burden of proof, and misunderstood the evidence regarding the mechanism of the fall.
The Court of Appeal unanimously rejected the plaintiff’s appeal.
Adamson J, with whom Basten JA and Emmett AJA agreed, found that there was no inadequacy in the trial judge’s reasoning, and that the trial judge had identified the competing inferences and concluded the evidence was insufficient to draw a conclusion that the lack of a balustrade was causative of the fall. There was no misapplication of the burden of proof given the various possible causes for the incident.
The Court of Appeal noted that it did not follow from the fact that there may be a greater risk of falling in absence of a balustrade that the plaintiff probably fell because there was no balustrade. To draw such an inference would elide the distinction between risk and causation.
Adamson J noted it remains a requirement of the law that a plaintiff prove that a defendant’s conduct materially caused the injury and the present state of authority does not accept the possibility of risk of injury as sufficient to prove causation.²
Basten JA held that in his view the plaintiff had also failed to establish that there was a breach of duty of care, in circumstances where the evidence indicated that the plaintiff had been a party to previous conversations discussing whether a balustrade should be installed, and it had been decided to take no action as a matter of convenience. In his Honour’s opinion, the plaintiff understood the risks posed by the absence of the balustrade and no breach of duty of care could be found in those circumstances.
This case reinforces the need for a plaintiff to establish causation in a way which identifies a cause of an incident as being more likely than other potential causes. If a court has competing inferences as to the cause of an incident, it cannot make a finding of negligence against a defendant.³
 Basten JA, Emmett AJA and Adamson J.
 Roads and Traffic Authority v Royal  HCA 19.
 Jones v Dunkel (1959) 101 CLR 298.