Causation

Causation - Magnifying glass on book

Introduction

Once established that the defendant fell below the expected standard of care, the plaintiff must prove, on the balance of probabilities, 1 that the breach(es) of duty caused the harm or loss suffered by the plaintiff.

Legal Principles to be Addressed

Civil liability legislation addresses the issue of causation as involving two distinct inquiries:

1) factual causation ; and 2) scope of liability. 2

Factual Causation

Factual causation involves asking the question of whether the Defendant’s negligence was a necessary condition for the occurrence of harm or loss that has been suffered.

In other words, ‘but for’ 3 the defendant’s failure would the harm have occurred anyway?

If the answer is no – then factual causation is satisfied, and one would move on to consideration of the second part of the causation inquiry — scope of liability.

However, if some factual uncertainty exists in that the ‘but for’ test is not sufficient to answer the question posed above, or to identify a singular cause of the harm or loss suffered by the plaintiff, the court may consider at this stage of the inquiry  ‘whether or not and why responsibility for the harm should be imposed on the negligent party’. 4 This allows the courts to make a value judgment where the negative criterion of the ‘but for’ test cannot be satisfied.

Factual causation in failure to give advice, information or warning cases

In cases in which there has been a failure to give information, advice or warnings about material risks involved in treatment, the common law approach, in determining the ‘but for’ question of causation, was to require express evidence of what the plaintiff would have done if properly warned. For example, if an operation carried risks that might end in total disablement, and the patient had been told about such risks, would the patient have decided not to have had the operation? Can they show evidence that this is the case? 5

That the Court will consider a person’s subjective evidence regarding what they would have done but for the failure to warn/provide advice or information is now also found in legislative provisions in New South Wales, Victoria, Western Australia, Queensland and Tasmania. However, in all such places except Victoria, such evidence can only be considered to the extent that it goes against the Plaintiff’s interests. 6 The provisions do not exist in South Australia, the ACT, or the NT.

Scope of Liability

The ‘scope of liability’ provisions include all other arguments regarding the attribution of legal liability for harm.

The inquiry at this stage encompasses considerations about whether or not, and if so why, the defendant should be found liable for the harm suffered by the plaintiff.

The inquiry may include for example, consideration of whether there were any new intervening acts that severed the chain of causation; or whether the harm/loss suffered was too remote a consequence of the Defendant’s actions to attribute liability to the Defendant. (These are discussed further below). Any other relevant matters may also be addressed.

The scope of liability inquiry will require the application of precedent (findings in previous cases) ‘as the legislative provision guides but does not displace common law methodology’. 7

In a novel case the Court must consider and explain in terms of legal policy whether or not, and if so why, responsibility for the harm should be imposed on the negligent party. 8

Consider the case of Wallace v Kam to further understand these principles as they were applied in a case that resulted due to a failure to warn of risks associated with undergoing a spinal operation.

New Intervening Acts

Chain of causation - broken - new intervening act
In the law of negligence, the causal link between the negligent conduct complained of, and the claimed loss may sometimes be severed by an event that occurs in between. If a subsequent event breaks the chain of causation, then it, and not the Defendant’s negligence, is the effective cause of the Plaitiff’s injuries, for the purpose of attributing legal responsibility.

To be sufficient to sever the causal connection, the intervening event must ordinarily be either –

  1. human action that is properly to be regarded as voluntary, or
  2. a causally independent event the conjunction of which with the wrongful act or omission is by ordinary standards so extremely unlikely as to be termed a coincidence. 9

When one of the above things occurs, the defendant may argue that the injury would not have occurred at all had the new intervening act not taken place, or that the plaintiff’s injuries would not have been as serious as they turned out to be. In the first situation the defendant attempts to argue that he or she should not be liable for the injuries at all. In the second situation, the defendant attempts to argue that he or she should not be liable for the injuries getting worse, but only for the initial injury caused by his or her negligence.

A qualification to this is that the Court will also consider if the act or event was ‘in the ordinary course of things …the very kind of thing likely to happen as a result of the defendant’s negligence’; and whether the D’s negligence created ‘the very risk of injury’ that has occurred. 10 That is, was the risk that eventuated ‘within the sphere of risk created by the defendant’s negligence’? If it is within the sphere of risk, the defendant will remain liable for all that has eventuated. If it is not, then the Court will determine whether the defendant should be liable at all, or for some part of the injury prior to the new act.

In health settings the issue of ‘new intervening acts’ may be relevant when a health practitioner is the person who commits the initial wrong causing harm or loss of some kind and some subsequent event occurs.

However, it may also be relevant when the health treatment provided to someone after they have suffered injury/harm elsewhere, is alleged to have been negligent. In such instances it may be argued that the negligent medical treatment was the cause of loss/harm or was responsible for its exacerbation (i.e. the medical treatment made the injury or harm worse). This was the case in Mahoney v Kruschich (Demolitions) Pty Ltd. 11 Please read the summary of Mahony to further understand the principles regarding when a new intervening act might break the chain of causation, and how that might be applied to medical contexts. It is noted here that the court in Mahony said that only negligence of a gross nature would be enough to break the chain of causation — but it is possible, depending on the circumstances, that a health practitioner would be liable for the damage to the extent that he or she shared responsibility for it.

Remoteness of Harm

Remoteness - Causation - Broken arm and neck brace
When considering remoteness of harm, the question asked is whether the Defendant should be required to compensate the Plaintiff for his/her injury/damage or whether the injury or damage is too remote a consequence of the Defendant’s negligence.

If the harm is considered too remote a consequence then causation in law will not be found and the Defendant will not be held liable.

To determine remoteness, the focus is upon whether the kind of damage (harm/loss) suffered was reasonably foreseeable. (Note, the test of reasonable foreseeability as applied to the remoteness inquiry differs from the test of reasonable foreseeability applied in relation to duty of care, and breach.) This may be framed in broad terms and does not have to be specific.

The precise manner in which the harm has come about does not need to be reasonably foreseeable. 12

The extent of the damage/loss/harm need not be foreseeable either. This is known as the ‘eggshell skull’ rule.

In Dulieu v White & Sons [1901] 2 KB 669, Justice Kennedy said:

“ If a man is negligently run over, or otherwise negligently injured, it is no answer to [his] claim for damages that he would have suffered less injury, or no injury at all, if he had not had an unusually thin skull or an unusually weak heart”.

That is, if physical injury was foreseeable, and the person has particularly brittle bones, the fact that their harm is more extensive than it would have been should the negligence have occurred in relation to someone that had strong bones, does not matter. This means one ‘must take their victim as they find them’ and such a consequence will not be considered too remote.

If the damage is not too remote, and all other issues regarding causation have been dealt with and do not serve to discount the Plaintiff’s claim, then the inquiry will move to consideration of whether there are any defences that may be raised.

Find out more

Notes:

  1. Civil Liability Act 2002 (NSW), s 5E; Wrongs Act 1958 (VIC), s 52; Civil Liability Act 1936 (SA), s 35; Civil Liability Act 2002 (WA), s 5D; Civil Liability Act 2003 (Qld), s 12; Civil Liability (Wrongs) Act 2002 (ACT), s 46; Civil Liability Act 2002 (TAS), s 14.
  2. Civil Liability Act 2002 (NSW), s 5D(1)(a) & (b); Wrongs Act 1958 (Vic), s 51(1)( & (b); Civil Liability Act 1936 (SA), s 34(1) & (b); Civil Liability Act 2002 (WA), s 5D(1) & (b); Civil Liability Act 2003 (Qld), s 11(1) & (b); Civil Liability (Wrongs) Act 2002 (ACT), s 45(1) & (b); Civil Liability Act 2002 (TAS) s 13(1) & (b).
  3. March v E and M H Stramare Pty Ltd [1991] HCA 12.
  4. Civil Liability Act 2002 (NSW), s 5D(2); Wrongs Act 1958 (VIC) s 51(2); Civil Liability Act 1936 (SA), s 34(2); Civil Liability Act 2002 (WA), s 5D(2); Civil Liability Act 2003 (Qld), s 11(2); Civil Liability (Wrongs) Act 2002 (ACT), s 45(2); Civil Liability Act 2002 (Tas), s 13(2).
  5. For an example of such a case, see Chappel v Hart (1998) 195 CLR 232.
  6. Civil Liability Act 2002 (NSW), s 5D(3); Wrongs Act 1958 (Vic) s 51(3); Civil Liability Act 2002 (WA) s 5D(3)(a); Civil Liability Act 2003 (Qld) s 11(3)(a); Civil Liability Act 2002 (Tas) s 13(3)(a).
  7. Wallace v Kam [2013] HCA 19 (8 May 2013) at [22].
  8. See Wallace v Kam [2013] HCA 19 (8 May 2013) at [23].
  9. Haber v Walker [1963] VR 339, p 358.
  10. March v Stramare per Mason CJ, p 518, 519; Mahoney v J Kruschich (Demolitions) Pty Ltd (1985) 156 CLR 522.
  11. Mahoney v Kruschich (Demolitions) Pty Ltd [1985] HCA 37; (1985) 156 CLR 522.
  12. See Jolley v Sutton London Borough Council [2000] 3 All ER 409 1 WLR 1082 (House of Lords); Hughes v Lord Advocate [1963] AC 837 (House of Lords); Doughty v Turner Manufacturing Co Ltd [1964] 1 QB 518.