Final Report on RREF 2001 - Department of Health

Part B: Development of Options for a Revised RREF
4.6 FURTHER ISSUES AND PREFERRED OPTIONS
Two aspects of differential weighting of the need variables were canvassed
in the consultations:
1. views as to the variables that warranted greater weight on the basis of
making a greater contribution to need for HACC services, and
2. the actual weight that each variable contributed to the model.
Variables warranting greater weighting
Participants in the Round 2 consultations expressed the view that some variables were seen to
have a greater bearing on need than others. The two variables that were most widely seen to
warrant more weight were rurality and socio-economic status, each identified in around 40% of
responses, followed by the health indicator and the residential care shortfall variable, each
identified in around 20% of responses. Only a minority of responses, around 10%, identified
cultural diversity and the Koori variable as warranting additional weighting.
At the same time, it was recognised that there were no clear empirical grounds for adjusting the
weightings and it was noted that any weighting based on arbitrary decisions would complicate
the process; even those who favoured giving additional weighting to some variables commented
that the process was imprecise. The option of further statistical modelling beyond the principal
components analysis already carried out was precluded by the lack of a measure of need that
could be used as the independent variable in methods such as regression analysis.
Actual contribution of variables to model
The scaling of all variables from 0 to 9 treats each variable as having an equal relationship to
need for HACC services. This equal treatment or equal weighting does not however mean that
each variable does in fact make the same contribution to overall need. The contribution that
each variable makes depends on the distribution of LGAs across the range of scores from 0 to 9.
A variable on which many LGAs receive a high scaled score will make a greater contribution to
the overall outcome than one on which only a few LGAs have a high scaled score and most
have lower scores.
Thus, as a large number of LGAs have a relatively high scaled score on median household
income, reflecting low socio-economic status, this variable contributes a large part of the overall
model. Similarly, a large number of LGAs receive a relatively high YLD and ARIA scores. In
contrast, only a small number of LGAs have a high proportion of their population that is Koori
and many LGAs receive a low scaled score on this variable.
The contribution that each variable makes to the revised RREF model is shown in Table 4.1 in
which the total points that each variable actually contributes are also expressed as a percentage
of the actual total of 1293.
Even without any further adjustment to take account of perceived relationships to need, it is
evident that each variable makes a different contribution to the overall model and so carries a
different weight. Thus, the Household Income variable contributes 494 points, 38.2% of the
total actual points, while the cultural diversity variable contributes 136 points and 10.5% of total
need. Given these differences, it may be more appropriate to refer to “unadjusted” weightings
rather than “even” weightings.
<strong>Final</strong> <strong>Report</strong> July 2001 46