Under ss 22(8)(b) and 22(8)(g) of the Return to Work Act 2014 (SA), 'disregarded' and 'deducted' express the same legislative intention: only impairment attributable to the relevant work injury is to be assessed for compensation. The Impairment Assessment Guidelines require a two-stage process: first assess the total WPI including all injuries, then deduct the impairment attributable to unrelated or previous injuries. The assessor is not required to make a separate stand-alone assessment of pre-existing impairment in accordance with the Guidelines but must estimate the degree of impairment from the unrelated cause and deduct it. However, the dissent of Kourakis CJ raises an unresolved tension regarding whether the approach conflates causal contribution with independent impairment assessment.
The full text is available to signed-in members, including the 1 later case that cites this judgment.
1 of the 1 citing case carries a classified treatment. How each court treated it is available to signed-in members.