Douglas, Richard --- "Counteracting hindsight bias in proof of 'but for' causation" [2020] PrecedentAULA 21; (2020) 157 Precedent 38

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COUNTERACTING HINDSIGHT BIAS IN PROOF OF ‘BUT FOR’ CAUSATION

By Richard Douglas QC

Australian law has long adopted a subjective test of causation in negligence cases where the breach of duty of care consists of a failure to give an appropriate warning or advice concerning risk of damage or injury.^[1] Professional negligence litigation features prominently in this space.

The salient question is whether, or how, the plaintiff – ‘but for’ the breach of duty – would have responded to the posited hypothetical warning or advice.

In this sphere, the common law – albeit supplanted in part by the Ipp Report legislative reforms – is still of critical importance to the adjudication of whether a plaintiff has discharged their onus of proving a causal nexus between the breach and damage.

This article canvasses both the common law position and legislative provisions.

COMMON LAW

In Chappel v Hart,^[2] Gaudron J said that where there is a duty to inform, ‘it is, of course, necessary for a plaintiff to give evidence as to what would or would not have happened if the information in question had been provided’.^[3] In support, her Honour referred to historical High Court authority in Duyvelshaff v Cathcart & Ritchie Ltd^[4] and Quigley v Commonwealth.^[5]

The more recent authorities have, however, eschewed such after-the-fact testimony from a plaintiff – except when the testimony was against the plaintiff’s interests – as to what he or she would have done if, hypothetically, the warning or advice had been given. Prior to the legislation resulting from the Ipp Report,^[6] this jurisprudential approach was used in weighing up the probative weight of the evidence, in contrast with its admissibility.^[7]

This approach was echoed in Rosenberg v Percival,^[8] where Kirby J wrote:

‘[M]ost judges ... today endeavour to rest their conclusions, as far as possible, on objective considerations, contemporaneous facts and logical inferences, rather than a self-claimed capacity to tell truth or falsehood by visual or aural impression.’^[9]

In Chappel v Hart,^[10] McHugh J encapsulated the foundation for this judicial preference in a medical negligence context, but in language of general application:^[11]

‘In practice, there is likely to be little difference in the application of the subjective and objective tests in medical issue cases. Human nature being what it is, most plaintiffs will genuinely believe that, if he or she had been given an option that would or might have avoided the injury, the option would have been taken. In determining the reliability of the plaintiff’s evidence in jurisdictions where the subjective test operates, therefore, demeanour can play little part in accepting the plaintiff’s evidence. It may be a ground for rejecting the plaintiff’s evidence. But given that most plaintiffs will genuinely believe that they would have taken another option, if presented to them, the reliability of their evidence can only be determined by reference to objective factors, particularly the attitude and conduct of the plaintiff at or about the time when the breach of duty occurred.’^[12]

Thus evidence of what transpired or was expressed at the time of, or shortly prior to, the damage being suffered, is ordinarily salient.

In Chotiputhsilpa v Waterhouse,^[13] the Court of Appeal found that the defendant, the NSW Roads and Traffic Authority, had breached its duty of care to the plaintiff, a young migrant pedestrian who was injured while attempting to cross the Anzac Bridge in Sydney, by failing to provide adequate directional signage to the pedestrian underpass. Causation was proved as the plaintiff had spent some time looking for a safe path to traverse the bridge before he ran across the roadway.

Habit or tendency in respect of the subject matter, albeit inadmissible as to a breach, may be admissible on causation, as exemplified by Hribar v Wells.^[14] In this case, on the issue of whether the plaintiff would have agreed to undergo the relevant surgery even if she had been given the appropriate warning, evidence was adduced – and given significant weight – to the effect that the plaintiff, historically, was compliant with advice given to her by medical advisors.

The plaintiff’s vanity can be relevant in this regard. In Bustos v Hair Transplant Pty Ltd,^[15] the plaintiff was found ‘keen to the point of desperation to undergo the procedures ... the only thing that would stop him was if it were effectively brought home to him that his appearance would be worse after the operation than before it’.^[16]

In Hoyts Pty Ltd v Burns,^[17] McHugh, Gummow, Hayne and Callinan JJ made the point that greater awareness of risks does not necessarily lead to a change of conduct on the part of the persons confronted by those risks.

IPP LEGISLATION

The Ipp legislation of each state and the ACT entrenched the common law subjective test for proof of causation.^[18]

The Ipp legislation in NSW, Qld, WA and Tas only, however, dealt with after-the-fact testimony.^[19] The NSW provision is representative:

‘5D General Principles

...

(3) If it is relevant to the determination of factual causation to determine what the person who suffered harm would have done if the negligent person had not been negligent:

...

(b) any statement made by the person after suffering the harm about what he or she would have done is inadmissible except to the extent (if any) that the statement is against his or her interest.’

As is plain from this provision, the enacting legislatures treated the issue in the procedural sphere of admissibility. Note, however, the ‘against interest’ exception.

Although the WA provision – due to its peculiar drafting – has been held to apply only to a natural person plaintiff,^[20] the provisions in NSW, Qld and Tas have been held to extend also to the evidence of the ‘guiding mind’ of a corporate plaintiff.^[21] The corollary is that in these states, the staff and directors of the corporation may give evidence as to how they would have responded had the appropriate warning or advice been given.

Understandably, a defendant’s counsel, in cross-examination of a plaintiff, may seek to elicit an admission that, in the event of a warning, the plaintiff would not have taken a different course. That stated, it has been held that the prohibition operates in respect of the evidence the plaintiff gives in-chief and during cross-examination.^[22] A direct question in cross-examination, ordinarily, would be characterised as unfair and thereby be disallowed.^[23]

Note that the statutory prohibition is not confined in operation to personal injury litigation.^[24]

It has been held, correctly, that such prohibition has no application to evidence that is sought to be adduced for the purpose of assessing damages. In McKenna v Fraser,^[25] the evidence in question consisted of statements made in the plaintiff’s quantum statement in which he stated that, but for the injury, he would have undertaken certain business activities. He argued that damages should be assessed on that basis. Justice North, over objection, permitted such evidence to be adduced:

‘When the report [the Ipp Report] and the cases referred to [therein] are considered it is plain that the section is directed to matters to do with “causation” in the context of the trial upon this issue of breach, not to the assessment of damages for loss of earning capacity. I think this is apparent from a reading of the section, and in particular, the context in which that section is to be found in the Act noting the provisions in the latter parts of the Act that deal with the assessment of damages.’^[26]

An instructive authority on the operation of the provision is Neal v Ambulance Service of New South Wales.^[27] This case concerned whether a plaintiff, absent a breach of duty, would have accepted advice as to treatment, and Basten JA (speaking for the Court) wrote of the NSW provision:

‘On one view, the difficulty of “counteracting hindsight bias” might have been thought to lie with the plaintiff. It seems unlikely that the provision was introduced to prevent the trivial waste of time which might attend the adducing and challenging of such evidence. Rather, the purpose of the provision appears to be to prevent a trial judge placing any weight on such evidence, in circumstances where it could not be said to be an abuse of his or her advantage as a trial judge. (Were it otherwise, an appellate court could intervene.)

Whatever the real purpose of the provision, the issue for determination is how a court is now to identify what course the plaintiff would have taken, absent negligence. That assessment might include evidence of the following:

(a) conduct of the plaintiff at or about the relevant time;

(b) evidence of the plaintiff as to how he or she might have felt about particular matters;

(c) evidence of others in a position to assess the conduct of the plaintiff and his or her apparent feelings or motivations; and

(d) other matters which might have influenced the plaintiff.

Properly understood, the prohibition on evidence from the plaintiff about what he or she would have done is of quite limited scope. Thus, the plaintiff cannot say, “If I had been taken to hospital I would have agreed to medical assessment and treatment”. Indeed, as the Negligence Review recognised, such evidence would be largely worthless. However, the plaintiff might have explained such evidence along the following lines:

I recall on the trip to the police station that I began to fell less well; my state of inebriation was also diminishing; I began to worry about the pain in my head ...

That evidence (entirely hypothetical in the present case) would not be inadmissible. If accepted, it might provide a powerful reason for discounting any inference as to future conduct drawn from the past refusal of treatment. It would constitute evidence as to the plaintiff’s position, beliefs and fears. Because an inference would need to be drawn from that evidence, no doubt the court would take into account the likely response of a reasonable person in such circumstances. That is consistent with the Act requiring that the matter be determined “subjectively in the light of all relevant circumstances”.’^[28] [emphasis added]

CONCLUSION

While the Ipp legislation has made inroads into this sphere of causation jurisprudence, the common law retains a crucial role in informing how the plaintiff discharges his or her onus on proving a causal nexus between the breach and damage. Disposition, contemporaneous conduct and knowledge of risk gravity are critical considerations when seeking to prove causation. In most cases, each consideration will trump after-the-fact testimony – if admissible – of a plaintiff’s likely response to a hypothetical warning or advice.

Richard Douglas QC is a barrister in practice in Callinan Chambers, Brisbane and is a member of Hemmant’s List. PHONE [phone] EMAIL [e-mail].

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^[1] Chappel v Hart (1998) 195 CLR 232, 247 (McHugh J), 272–3 (Kirby J).

^[2] Ibid.

^[3] Ibid, 239.

^[4] [1895] ArgusLawRp 104; (1973) 1 ALR 125.

^[5] (1981) 35 ALR 537.

^[6] Review of the Law of Negligence Report (Final report, September 2002) (Ipp Report).

^[7] Rosenberg v Percival [2001] HCA 18; (2001) 205 CLR 434; see also Hoyts Pty Ltd v Burns [2003] HCA 61; (2003) 201 ALR 470; and as to admissibility, Seltsam Pty Ltd v McNeill [2006] NSWCA 158, [112]–[124].

^[8] Rosenberg v Percival, ibid; see also [87]–[89] (Gummow J), [221] (Callinan J); see also Vairy v Wyong Shire Council [2005] HCA 62; (2005) 221 ALR 711, [226] (Callinan and Heydon JJ).

^[9] Rosenberg v Percival, ibid, [163].

^[10] See above note 1.

^[11] See also Hoyts Pty Ltd v Burns [2003] HCA 61; (2003) 201 ALR 470, [54] and [57] (Kirby J).

^[12] Chappel v Hart, above note 1, footnote [64].

^[13] [2005] NSWCA 295; cf Commissioner of Main Roads v Jones [2005] HCA 27; (2005) 215 ALR 418.

^[14] [1995] SASC 5111; (1995) 64 SASR 129, 140 (Bollen J).

^[15] (Unreported, Court of Appeal, 15 April 1997).

^[16] Ibid, 17.

^[17] [2003] HCA 61; (2003) 201 ALR 470, [14]; see also Enright v Coolum Resort Pty Ltd [2002] QSC 394.

^[18] Civil Liability Act 2002 (NSW) (NSW Act), s5O(3)(a); Wrongs Act 1958 (Vic), s51(3); Civil Liability Act 2003 (Qld) (Qld Act), s11(3)(a); Civil Liability Act 1936 (SA), s34(2); Civil Liability Act 2002 (WA) (WA Act), s5C(3)(a); Civil Liability Act 2002 (Tas) (Tas Act), s13(3)(a); Civil Law (Wrongs) Act 2002 (ACT), s45(2)(a).

^[19] NSW Act, s5D(3)(b); Qld Act, s11(3)(b); WA Act, s5C(3)(b); Tas Act, s13(3)(b).

^[20] AVWest Aircraft Pty Ltd v Clayton Utz [2018] WASC 167.

^[21] In the matter of Metal Storm Limited (In Liquidation) (No 2) [2019] NSWSC 1682.

^[22] LK v Parkinson [2009] NSWDC 47, [6]–[7].

^[23] Ralston v Jurisich [2017] NSWCA 63, [83]–[86], the putative disallowance being under the Evidence Act 1995 (NSW), s135.

^[24] Lym International Pty Ltd v Marcolongo [2011] NSWCA 303.

^[25] [2014] QSC 14.

^[26] Ibid, [5].

^[27] [2008] NSWCA 346.

^[28] Ibid, [39]–[42].