Are disability weights universal? Ranking of the disabling effects of different health conditions in 14 countries by different informants1

measures of population health (SMPH) provide a " common metric " for a wide range of health evaluations such as effectiveness of interventions or efficiency of health systems (WHO 1996). This metric adds " disability " (i.e. non-fatal health outcomes) to mortality, and thus results in a more realistic measure than what is obtained by measuring mortality alone (Murray and Lopez 1997). In the course of this book various attempts are made to develop composite health measures that combine information on mortality and non-fatal health outcomes to represent population health in a single number. However, the cross-cultural applicability of these methods as well as the equivalence of derived preferences has not been standardized globally, regionally and nationally. Because of international comparability, great care must be taken in the construction of SMPH which involves value judgements in the calculation of the disability component in these measures captured in " disability weights " (also known as preferences, valuations, or utilities). A disability weight assigns a single numerical value to a given state that is worse than perfect health. We convert multiple aspects of disability (e.g. cogni-tion, mobility, self-care, interpersonal relations, work or household activities , etc.) into a single number. The health status descriptions of some selected domains are transformed through a " cognitive exercise " to a value or preference that is usually elicited by the importance given to the condition , or by trading risks, time, money or personal lives. Usually a perfectly healthy state is given a weight of 0, and death is equivalent to a weight of 1. This disability weight, as a matter of fact, has the same anchor value for disability-adjusted life years (DALYs) or quality-adjusted life years (QALYs). The main difference is the sign. For DALYs the value is taken negatively (disability), for QALYs positively (quality of life). In the original Global Burden of Disease (GBD) study these weights were determined with professional health care providers through the person trade-off (PTO) method (Nord 1995). Professional health care providers were chosen because they are thought to be familiar with health conditions and their outcomes, a familiarity that makes it easier to draw the often complex comparisons between the impacts of different disease states required by the PTO protocol. These professionals were assumed to be representative of society as a whole. This theoretical assumption, however, requires empirical support. For empirical testing, preference measures should also be obtained …