Australia: Medical Assessors Empowered To Assess Causation

Last Updated: 3 September 2009
Article by Cherilyn Ribbons and Peter Hunt

Ackling v QBE Insurance (Australia) Limited and Anor [2009] NSWSC 8814

Supreme Court of NSW1

In Brief

  • MAS Assessors have the power to assess causation.
  • Assessing causation is part and parcel of assessing s 60 issues of whole person impairment and stabilisation.
  • Section 58(1)(d) operates to ensure the consideration of causation when assessing whole person impairment.
  • The manner in which causation is to be assessed is in keeping with the statutory provisions and delegated legislation.


The plaintiff sought a determination from MAS that his psychological injury had stabilised and exceeded the 10% threshold.

Assessor Parsonage issued Certificates, dealing relevantly with the issues of stabilisation and permanent impairment.

Both Certificates stated that the psychiatric injury was not related to the accident, specifically: "NIL diagnosed psychiatric disorder related to the motor accident."

The finding of Assessor Parsonage did not mean that the plaintiff did not have a psychiatric disorder. To the contrary, the Assessor concluded that the plaintiff had developed a major depressive disorder subsequent to an unrelated incident occurring after the subject accident.

Review Panel Decision

Shortly after receiving the Assessment Certificates, the plaintiff lodged an Application for Review with MAS and the defendant lodged its Reply.

The plaintiff argued that the Assessor had erred in his assessment of causation of the plaintiff's psychiatric disorder. The defendant agreed with this, submitting in the Reply form that the Assessor's approach on the issue of causation was incorrect.

A Review Panel was convened by MAS and consisted of three psychiatrists who ultimately determined that Assessor Parsonage had not erred in his findings. The Review Panel found that there was no evidence that the disorder had been present prior to the second accident and therefore there was no assessable psychiatric impairment arising from the first accident.

Supreme Court Decision

The plaintiff sought relief in the Supreme Court, chiefly on the basis that the Certificate issued by the Review Panel contained a jurisdictional error, because the Motor Accidents Compensation Act (MAC Act) did not permit an Assessor to make a determination as to the causation of impairment.

further ground of alleged error was that the Assessor erred in the method of determining causation. The plaintiff submitted that the Assessor should have invoked the principles set our in March v Stramare2 wherein causation is a matter of common sense and that the "but for" test is not the only method to determine causation.

The Court observed that s 60(2) lists the types of disputes MAS may assess, and while causation is not one of the issues listed, the determination of "causation" was part and parcel of determining a dispute on whole person impairment and stabilisation. The parties cannot seek to have part of a dispute determined.

His Honour was satisfied that it was within the scope of a Medical Assessor's power to express a conclusion on causation in the course of determining questions on permanent impairment, "as the function of a Medical Assessor or Review Panel is to consider the medical dispute referred for the purpose of discharging jurisdiction under the MAC Act. The scope of the medical dispute is not controlled or confined by the terms of the medical reports furnished by the parties" (paragraph 84).

While his Honour determined that the Medical Assessor and the Review Panel had not erred in addressing the issue of causation, his Honour accepted the defendant's concession that the manner in which causation had been determined was incorrect. Specifically, his Honour stated at paragraph 24:

"QBE accepted that the Medical Assessor and the Review Panel both applied an incorrect test of causation. Mr Snell, counsel for QBE, submitted that Medical Assessor Parsonage had simply observed that there had been no psychiatric symptoms prior to the January 2004 accident. As a consequence of this error, QBE consented to a review being granted. QBE submitted that the Review Panel fell into the same error on causation by looking only for evidence of psychiatric/psychological treatment or complaints prior to 21 January 2004. Mr Snell submitted that the Review Panel should have considered whether the aggravation of physical symptoms on 21 January 2004 was causally connected to the 2003 motor vehicle accident, and whether psychiatric symptoms developing after 21 January 2004 were therefore causally connected to the earlier motor vehicle accident."


The decision in Ackling v QBE confirms that a Medical Assessor - and a Review Panel - may assess causation as part of their statutory duty to assess permanent impairment and stabilisation. However, the Court failed to provide any useful guidance as to the test to be applied. All that the Court determined was that the Medical Assessor applied the wrong test by merely focussing on whether there were any psychiatric symptoms between the first and second accidents; rather than adopting the more robust approach of considering whether the physical injuries sustained in the first accident contributed to the development of psychiatric symptoms after the second accident.

The case does not specifically address the critical question of whether a MAS Assessor's assessment of causation is binding on the parties. However, the Court's reasoning provides some support for the argument that a MAS assessment on causation is binding in both Court proceedings and before CARS.

Section 58 empowers a Medical Assessor to assess "medical assessment matters" including "whether the degree of permanent impairment of the injured person as a result of the injury caused by the motor accident is greater than 10%." Given the decision in Ackling v QBE, such an assessment may include an assessment of causation.

If it is accepted that "causation" is, therefore, implicitly a "medical assessment matter" - even though it is not listed as a separate item in s 58 - then it follows that the Medical Assessor's decision on causation is binding on the parties given s 60(2), which provides:

"Any such certificate as to a medical assessment matter is conclusive evidence as to the matters certified in any court proceedings or in any assessment by a claims assessor in respect of the claim concerned."


1. Johnson J

2. (1991) 171 CLR 506

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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