Seminario 15/12: F. I. Sánchez-Martínez (U. Murcia) – Avoiding preference reversals with opaque methods

Información

Abstract

Two major classes of preference elicitation methods are Matching and Choice. In Matching Methods, respondents are asked to establish indifference between two options. Very often, Choice and Matching seem to reveal opposite preferences, a phenomenon known as “preference reversals”. We study if there are elicitation methods that reduce or eliminate this discrepancy between Matching and Choice in the domain of the evaluation of health outcomes. This is an important topic since a systematic discrepancy between Matching and Choice in the evaluation of health states violates “procedure invariance”, one of the cornerstones of rational choice. We present the results of an experiment comparing several matching procedures with preferences elicited in direct choices. All matching methods are choice-based, that is, they match two options using converging sequences of choices (Choice-Based Matching – CBM). Our main finding is that the Choice-Matching discrepancy is not avoided simply by moving from standard matching to CBM. The rate of preference reversals decreases when CBM methods hide respondents the final goal of the sequence of choices (what we call ‘non-transparent’ or ‘opaque’ methods). That is, when subjects do not see that each choice is part of a sequence aimed at establishing indifference between options. This seems to confirm Fischer et al’s (1999) task-goal hypothesis that has not been tested previously in health economics.