Where it is determined that two impairments are to be combined, use the Combined Values Chart to calculate what the combined percentage is, expressed as one figure.
Down the left side (row) of the chart is one set of figures and along the bottom (column) are others. Use the left side (row) figures for the condition that has the greater WPI. The bottom (column) side is used for the other, lesser WPI. By intersecting the row and column, a combined figure can be determined.
It is important to understand that CWPI is not a simple addition of two or more WPIs; the effect of the use of the Combined Values Chart is to derive a CWPI value which is less than an addition of the constituent WPIs. As an example of this, the combination of a WPI of 15 under Table 10.2 (Lower Urinary Tract) and a WPI of 10 under Table 11.1 (Male Reproductive System) results in a CWPI of 24 under the Combined Values Chart.
Where there are more than two impairments, carry out the above process for the first two impairments, beginning with the two highest WPIs. Determine what the combined figure is, and then use that combined figure and the next highest WPI for a total combined percentage.
Continue this process until all impairments have been included. The final figure is the CWPI.
Note that the Combined Values Chart must NOT be used to combine impairments caused by separate injuries. In this case there should be completely separate calculations of entitlement to compensation for permanent impairment.
References
- Approved Guide Principles of Assessment
- Canute v Comcare (2006) HCA 47 : discrete injuries to be assessed separately