The effect of bi-criteria conflict on matching-elicited preferences

International audienceWe focus on multicriteria preference elicitation by matching. In this widely employed task, the decision maker (DM) is presented with two multicriteria options, a and b, and must assess the performance value on one criterion for b, left blank, so that she is indifferent between the two options. A reverse matching, which is normatively equivalent, can be created by integrating the answer to the description of b and letting the DM adjust a performance value on the previously totally specified option a. Such a procedure is called a bi-matching. Consistency requires that isopreferences resulting from the forward and backward matchings be identical, but they empirically differ in a systematic direction. In a matching task, multicriteria conflict refers to the magnitude of the advantage or disadvantage to be compensated. We investigate the effect of the multicriteria conflict, or trade-off size, on the difference of judgement between forward and backward matchings. We observed that the difference of judgement is increased both by multicriteria conflict and by asking deteriorating rather than improving judgements at both steps of the bi-matching. We derive some implications for the practice of preference elicitation

The measurement of quality-adjusted life years: investigations into trade-offs between longevity and quality of life

In health care, decision makers are faced with increasing innovation and demand for services accompanied by escalating costs. As a result, governments and institutions have sought to promote health care value (i.e. better outcomes per moneys spent). A summary measure of health-related quality-of-life (HRQoL) to help decide how to allocate available resources is thus highly desirable. In no other area of public policy has a measure similar to the widely-used quality-adjusted life-year (QALY) been developed. The QALY is therefore unique in both its ambitions and in the political, philosophical and measurement challenges it faces. This thesis set out to examine health state valuation using the time-trade off (TTO), a tool used to measure HRQoL, in the context of a behavioural economic framework. Observed violations of procedural and descriptive invariance, cornerstones of decision theory (on which the TTO is based), have been witnessed in health state valuation and elsewhere. Behavioural economics offers a framework by which such inconsistencies can potentially be better understood. Although behavioural economics has gained traction in other areas of decision research, its application to health state valuation has been limited. Drawing on the decision-making literature and health-specific considerations, the empirical studies in this thesis: provide insight into why previous studies of the TTO have yielded inconsistent findings, showcase violations of internal consistency due to behavioural economic phenomena, and identify issues relevant to the choice of TTO ‘version’ (i.e. how values should be elicited). Implications of the research in terms of stated preference methods and their role in policy are discussed. A strict focus on the TTO was intended, as it is the tool most widely implemented in health state preference elicitation, both in research contexts and clinical studies that seek to demonstrate cost-effectiveness. However, importantly, the empirical findings and discussion in this thesis are relevant not only to researchers of health state valuation but to policy makers in health and other areas of social policy which seek input for their decisions through stated preference exercises