Improving the Valuation of the EQ-5D-5L by Introducing Quality Control and Integrating TTO and DCE

Background: Recently, a new version of the standard EQ-5D questionnaire called EQ-5D-5L with 5 levels on each dimension was developed. To make the EQ-5D-5L suitable for use in economic evaluations, national value sets need to be developed. A standardized valuation protocol has been suggested for that purpose, to enable comparison of values across countries. This protocol included two elicitation techniques, the ‘composite time trade-off’ (C-TTO), and ‘discrete choice experiments’ (DCE).
This thesis describes experiences with first use of that standardized protocol and major evolvements happening to it since, with a focus on the following three questions:
1) What problems may be encountered in the use of the EQ-5D-5L valuation protocol to generate national value sets?
2) How can the protocol be improved?
3) How can the produced data best be modelled to develop a value set?
Conclusions: The studies presented in this thesis, together with similar work accomplished elsewhere, have resulted in an evolved valuation protocol for the EQ-5D-5L instrument, paired with a quality assurance procedure and novel analytical approaches. The updated protocol has enabled teams from all over the world to successfully establish EQ-5D-5L value sets.