The difficulty with this approach as that it makes determination of the relative importance of
different forms of physical quality of life/objective well-being exceptionally difficult, as the
subject's own view of relative desirability would be precluded. Either one does not develop
a global index, or one arbitrarily assigns weightings so that dimensions/sub-scales can be
combined to form a global index. Kaplan, Bush and Berry (1979) have referred to this issue
in suggesting that the category rating task allows a single global rating to be given to total
case descriptions so that the subject can consider the multiple dimensions of health jointly
and simultaneously, and argue that this is necessary if arbitrary rules for combining
attributes into a total case rating are to be avoided. A different means of using patient
report to weight dimensions has been noted by Goodinson and Singleton (1989), who refer
to a 1985 study by Ferrans and Power where Likert scales were used to measure
satisfaction and then measures were obtained on the relevance of each item/domain to the
individual, an aggregate QOL index formed by weighting each item/domain according to its
reported relevance value and then adding together.