The information content of the WTP-WTA gap: An empirical analysis among severely ill patients

Large disparities between willingness to pay (WTP) and willingness-to-accept (WTA) are commonly encountered in empirical studies and raise some important controversies. Nevertheless, the relationships between WTA and WTP can help understand not only how a service is valued but also how it can be substituted or how its loss can be resisted. The purpose of this study was to examine cancer patients’ preferences for blood transfusion setting from the perspective of WTA and WTP. A contingent valuation (CV) survey was administered to 139 patients receiving transfusions either at home or in the hospital. While few patients (6%) gave WTP protest responses, the WTA approach generated more protest responses (18%). The WTA-WTP discrepancy was confirmed. One in four of the patients reported that no amount was deemed sufficient to compensate for the renunciation of their home BT management. The main determinants of WTP were significantly different from WTA predictors. Our results suggest that individuals’ strategies towards constructing WTP and WTA differ in terms of determinants, reasoning, use of information and economic rationality. They give empirical evidence on the usefulness to elicit both WTP and WTA responses in healthsurveys to help understand the economic evaluation of health technology assessment and care organization.