Some estimates have been made of the value of a QALY based either on modelling approaches or survey research. Modelling has essentially involved
- taking an existing value of a prevented fatality (VPF),
- assuming an age at which the fatality would have taken place (typically around 40 years), using actuarial data to project future survival prospects if the fatality were prevented, adjusting such future life years gained by age-related quality of life scores (where 0=death and 1=full health), to arrive at QALYs, and discounting these QALYs, and
- dividing the VPF by the QALYs gained. This approach has been used in the US (Hirth et al., 2000) and is limited in that WTP for a reduction in risk of premature death is assumed to be the same as the WTP for the preservation of a given number of equally valued future QALYs.
More sophisticated models for deriving a value of a QALY, which have not been used before, would be estimated in work package 1 of EuroVaQ, permitting improved and European-relevant estimation of WTP-based values of a QALY in the short-term. There have been no such values of QALYs based on prevention of non-life-threatening illnesses where QALYs arise from gains in quality of life only. Again, new and original values would be produced in work package 1.
Cluster 1 - Work package 1
In this part of the project, to be conducted during the first 15 months, and covering work package 1, the literature on contingent-valuation-based values for health and safety will be comprehensively reviewed and appraised. Consideration will be directed towards how far inferences can be drawn from these studies to guide judgments about the methods for converting existing valuations of statistical lives established in the transport safety field to societal values of QALYs. When making such estimates, assumptions and caveats will be clearly specified. This investigation will not only be limited to published studies but will include a summary of existing procedures in various Ministries using explicit references to monetary values of statistical lives to inform decisions.
One advantage the research team has is direct access to a substantial body of raw data not only from the 'final' studies we have conducted but also from the considerable amount of piloting and developmental work we have undertaken during the past two decades. Many of these data have not been published in journals, and have often only appeared in summary form in reports; but we believe they may constitute a valuable additional source of evidence. These data sets have already been revisited in the UK as part of an exercise to devise new models for converting from the value of a prevented fatality (VPF) and values of serious injuries (VSIs) to the value of a QALY. The feasibility of using these models in all participating countries will be explored.