QALYs versus HYEs
At a normative level, there is also the need for criteria to be established by which a
choice between the value of a whole profile and the combined value of different states
can be made. For example, if a future health state is not known with certainty, it might
be more appropriate to value the previous state independently so that the future state does
not contaminate its value. And even if there is knowledge about future health, it might still
be considered appropriate to elicit the “goodness” associated with each state in isolation
of other states (2). This suggests that in some circumstances the QALY model might be
more suitable than the HYE model, even if the sum of the parts does not provide a good
approximation of the whole.
All of this raises interesting questions about how health states or profiles should be
presented to respondents. It is likely that most people would recognize that their health
will deteriorate over time, but most would not allow the value of their current health to be
affected by such knowledge (unless they are explicitly asked to, of course). It is remarkable
that these central questions have been almost completely ignored as the debate has focused
instead on the relative merits of different valuation procedures.
This paper has highlighted some of the important theoretical and empirical questions
relating to precisely what should be valued, and it is hoped that future research will address
them. Ultimately, though, whether any of these issues matters in a policy sense will be de-
termined by whether resource allocation decisions are affected by using QALYs as opposed
to HYEs, and this is perhaps the research question.
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