Introduction
1. Since 2008, our preferred measure of health-related quality of life in adults has been EQ‑5D. For most of that time, there has been only 1 version of the descriptive system, EQ‑5D‑3L. In this version, respondents rate their degree of impairment in different health domains using 3 response levels (no problems, some problems and extreme problems). The EuroQol Group has created a new descriptive system, EQ‑5D‑5L, with 5 response levels (no problems, slight problems, moderate problems, severe problems and extreme problems). EQ‑5D‑5L was designed to be more sensitive than EQ‑5D‑3L.
2. Our current guide to the methods of technology appraisal 2013 states that data collected using the EQ‑5D‑5L descriptive system may be used for reference-case analyses. When the guide was written, there was no value set for EQ‑5D‑5L from which to derive utilities. Section 5.3.12 of our methods guide, states that: 'Until an acceptable valuation set for the EQ‑5D‑5L is available, the validated mapping function to derive utility values for the EQ‑5D‑5L from the existing EQ‑5D (‑3L) may be used (available from http://www.euroqol.org)'.
3. An EQ‑5D‑5L value set for England has been published (Devlin et al. 2018). Independent quality assurance (Hernandez Alava et al. 2018) and reports from 4 independent experts raised concerns about the quality and reliability of the data collected in the valuation study, and the methods used to model these data. Accordingly, we've chosen not to use the EQ-5D-5L value set for England published by Devlin et al (2018). The English valuation study was one of the first to be carried out anywhere in the world. Since then the international standard valuation study protocol has been improved and additional quality control methods introduced.
4. This position statement applies to all guidance-producing programmes at NICE that use cost-utility analyses.