Value of a QALY and VSI estimated with the chained approach

The value of a quality-adjusted life-year (QALY) and the value of a statistical injury (VSI) are important measures within health economics and transport economics. Several studies have, therefore, estimated people's willingness to pay (WTP) for these estimates, but most results show scale insensitivity. The 'original' chained approach (CA) is a method developed to mitigate this problem by combining the contingent valuation (CV) with standard gamble (SG). In contrast to the version of the CA applied by the previous research of the WTP for a QALY, the original version allows the value of major health gains to be estimated without having the respondents express their WTP directly. The objective of this study was to estimate the value of a QALY and VSI in the context of non-fatal road traffic accidents using the original CA to test if the approach, applied to a wide range of health gains, is able to derive valid estimates and a constant value of a QALY which the previous research has not been able to show. Data were collected from a total of 800 individuals in the Swedish adult general population using two web-based questionnaires. The values of a QALY based on trimmed estimates were close to constant at €300,000 irrespective of the size of the QALY gain. The study shows that the original CA method may be a valid method to estimate the value of a QALY and VSI for major health losses. It also supports the use of a higher threshold value for a QALY than that which is currently applied by several health technology assessment agencies in different countries.