Impairments must be caused by accepted injuries to be compensable. Section 4 of the DRCA defines an 'impairment' as:
- the loss, the loss of the use, or the damage or malfunction, of any part of the body or of any bodily system or function or part of such system or function.
The Guide to the Assessment of the Degree of Permanent Impairment 2023 (the DRCA PI Guide) is used to assess Defence-related claims. The DRCA PI Guide expands on the definition of impairment in the 'Principals of Assessment' to include:
- the health status of an individual and includes anatomical loss, anatomical abnormality, physiological abnormality and psychological abnormality.
The degree of impairment is assessed by reference to the impact of that loss by reference to the functional capacities of a normal healthy person. Impairment is measured against its effect on personal efficiency in the activities of daily living in comparison with a normal healthy person.
Whole Person Impairment (WPI) is defined in the Introduction of the DRCA PI Guide, as:
- the methodology used in this Guide (and in previous editions of this Guide) for expressing the degree of impairment of a person, resulting from an injury, as a percentage. The concept of WPI is drawn from the AMA Guides (where it is referred to as “whole man” impairment).
While the Approved Guide tries to encompass the concept of WPI, the High Court decisions in Canute v Comcare (2006) HCA 47 (Canute) and Fellowes v MRCC [2009] HCA 38 (Fellowes), as well as the Full Federal Court decision in Robson v MRCC [2013] FCAFC 101 (Robson) must be considered in determining which impairment values are combined, and which must be assessed separately. See chapter 3.4 for more information on WPI.