A program of methodological research to arrive at the new international EQ-5D-5L valuation protocol

To describe the research that has been undertaken by the EuroQol Group to improve current methods for health state valuation, to summarize the results of an extensive international pilot program, and to outline the key elements of the five-level EuroQol five-dimensional (EQ-5D-5L) questionnaire valuation protocol, which is the culmination of that work.

To improve on methods of health state valuation for the EQ-5D-5L questionnaire, we investigated the performance of different variants of time trade-off and discrete choice tasks in a multinational setting. We also investigated the effect of three modes of administration on health state valuation: group interviews, online self-completion, and face-to-face interviews.

The research program provided the basis for the EQ-5D-5L questionnaire valuation protocol. Two different types of tasks are included to derive preferences: a newly developed composite time trade-off task and a forced-choice paired comparisons discrete choice task. Furthermore, standardized blocked designs for the selection of the states to be valued by participants were created and implemented together with all other elements of the valuation protocol in a digital aid, the EuroQol Valuation Technology, which was developed in conjunction with the protocol.

The EuroQol Group has developed a standard protocol, with accompanying digital aid and interviewer training materials, that can be used to create value sets for the EQ-5D-5L questionnaire. The use of a well-described, consistent protocol across all countries enhances the comparability of value sets between countries, and allows the exploration of the influence of cultural and other factors on health state values.