The recent decision of McQuitty provides important guidance to Queensland personal injury practitioners with respect to the impact of hypothetical events, pre-existing injuries or conditions and the assessment of damages. The probability test applied by His Honour Jackson J may assist defendants to reduce an award of damages in claims for personal injuries where the plaintiff has pre-existing injuries or conditions which had a probability of impacting a head of damage.1

In McQuitty the plaintiff was a passenger in a car involved in a serious motor vehicle accident. Liability was admitted. Quantum was in dispute. The plaintiff had a troubled past having a history of substance abuse, limited work history, behavioural issues and had been involved in at least two previous serious motor vehicle accidents.

The plaintiff contended that the “pre-existing behaviours were not relevant to decrease the amount of damages to be awarded” on the basis that “the defendant must take the plaintiff as they find them” (the egg-shell skull rule).2 In support of this position the plaintiff relied upon the decision of Watts v Rake (1960) 108 CLR 158 and Purkess v Crittenden (1965) 114 CLR 164 which would require the Court to assess “whether the pre-injury evidence was sufficiently precise and definite (author’s emphasis added) to displace an inference that the disabling condition was caused by the injury”.3

Jackson J considered the plaintiff’s reliance on Watts v Rake and Purkess v Crittenden was inconsistent with Malec v JC Hutton Pty Ltd (1990) 169 CLR 638 which requires the assessment of past and future hypothetical events on the basis of the “degree of probability” “having regard to the possibilities between 0 per cent and 100 percent”.4 His honour determined that in the event of any inconsistency the rule in Malec was to be preferred.5 Accordingly, the defendant was not required to undertake a precise assessment of probabilities, rather the Court is only required to evaluate possibilities with appropriate allowanced being made for these contingencies.6

The McQuitty decision clarifies the evidence required by a defendant to establish possible contingences which may have contributed to a plaintiff’s condition and related head of damage. With a lower threshold to be applied in such cases a defendant may successfully reduce an award of damages where a pre-existing condition had a possibility of harmful consequences to the plaintiff.

A further matter of interest to practitioners is the commercial care rate for gratuitous care applied by His Honour at $44.25 per hour. It is assumed that the hourly rate applied for gratuitous care will be subject to the appeal.