Measuring the health of populations: the veil of ignorance approach

Abstract

We report the results from two surveys designed to explore whether an application of Harsanyi's principle of choice form behind a veil of ignorance (VEI) can be used in order to measure the health of populations. This approach was tentatively recommended by Murray et al. (Bull. World Health Organ 2000; 78 : 981-994; Summary Measures of population health: Concepts, Ethics, Measurement and Applications, WHO, 2002.) as an appropriate way of constructing summary measures of population health (SMPH) for comparative purposes. The operationalization of the VEI approach used in this paper was suggested by Nord (Summary Measures of Population Health: Concepts, Ethics, Measurement and Applications, WHO, 2002.). We test if VEI and person trade-off (PTO) methods generate similar quality-of-life weights. In addition, we compare VEI and PTO weights with individual utilities estimated by means of the conventional standard gamble (SG) and a variation of it we call double gamble. Finally, psychometric properties like feasibility, reliability, and consistency are examined. Our main findings are next: (1) VEI and PTO approaches generate very different weights; (2) it seems that differences between PTO and VEI are not due to the 'rule of rescue'; (3) the VEI resembled more a DG than a classical SG; (4) PTO, VEI, and DG exhibited good feasibility, reliability and consistency. Copyright © 2004 John Wiley & Sons, Ltd.

The lack of theoretical support for using person trade-offs in QALY-type models

“…Although these methods may refer to a probabilistic framework that is different from ours (depending on the specific interpretation of the questions involved), the same basic problem is present with the use of a veil-of-ignorance-based index as quality-adjustment factor in a QALY model (or disability weight in a DALY model). An interesting recent experiment [34] has, however, indicated that a veil-of-ignorance-based index is closer to an individual quality-adjustment factor than a person trade-off based index, which therefore in this respect reduces the practical importance of a potential conflict with the Pareto principle.…”

“…Procedures related to person trade-off called veil-ofignorance methods have also recently drawn some attention (e.g., [23,30,34]). Although these methods may refer to a probabilistic framework that is different from ours (depending on the specific interpretation of the questions involved), the same basic problem is present with the use of a veil-of-ignorance-based index as quality-adjustment factor in a QALY model (or disability weight in a DALY model).…”

“…However, since the point of departure of the QALY literature proposing use of person trade-off indices is that such indices and individual quality-adjustment factors based on time trade-offs measure two different things [which they certainly also do in our general model (3) unless w(a i , t i ) = f(a i )t i ], and since experiments have indicated considerable discrepancies between these indices (e.g. [33,34,36]), inherent in this approach is therefore a conflict with the Pareto principle. Even assuming that QALYs are relevant at individual and societal levels, making use of a criterion of the kind (4) does not have theoretical justification.…”

The influence of probabilities on the response mode bias in utility elicitation

“…Building on these initial results, research on the sources of bias in eliciting utility functions has been particularly eminent in the 1980s (e.g., Tversky and Kahneman 1981;Hershey et al 1982;Hershey and Schoemaker 1985;de Neufville 1984, 1986;Johnson and Schkade 1989;Schoemaker and Hershey 1992), but this topic also plays a major role in more recent research (e.g., Starmer 2000;Loubergé and Outreville 2001;Abdellaoui et al 2005;Maule and Villejoubert 2007). In particular, there have been several studies in the domain of health-related decisions, which investigate inconsistencies in utility elicitation (e.g., Bleichrodt et al 2001;Oliver 2003;Pinto-Prades and Abellán-Perpiñán 2005;Bleichrodt et al 2007). …”

Population health. More than the sum of the parts?

“…11 Wolfson described this as the necessary differentiation between the size of the pie and the manner in which the pie is divided (page 175). 15 Nord, 16 and Pinto-Prades and Abellan-Perpinan 17 are counter examples to this trend, and have touched on the legitimacy of the separation-but tangentially. They considered people's preferences for two populations with different mixes of health states.…”