Comparing the Monetary Value of a Quality-Adjusted Life Year from the Payment Card and the Open-Ended Format
Abstract Background: The payment card (PC) format and the open-ended (OE) format are common methods in eliciting willing-to-pay (WTP) of one additional quality-adjusted life year (QALY). The aim of this research is to compare these two formats in eliciting the monetary value of a QALY.Methods: A contingent valuation survey was carried out using a pre-designed questionnaire with various hypothetical scenarios. The difference between the PC and the OE formats was evaluated by a two-sample equality test. Furthermore, regression analysis was carried out to control observed heterogeneity and to test theoretical validity.Results: In total, 461 individuals were involved, among whom 235 (51%) answered the PC question, while 226 (49%) answered the OE question. No significant difference was observed between the median of these two methods. However, in the subgroup analysis, noteworthy differences were noticed in the median for these two formats in all scenarios. Both formats were proved to be theoretically valid, whereas the OE technique was found to have a stronger association with all variables in the regression model than that of the PC format. Moreover, joint estimation indicated a positive but not significant effect on the OE results.Conclusions: This research indicated that there was no statistical difference between the PC format and OE format and proved the validity of both, which justified the combined use of these two methods in eliciting monetary value of QALY. More research about the difference and the validity of various WTP eliciting methods would be needed for a robust estimation of WTP/QALY.