Competing interests
David GT Whitehurst is a member of the EuroQol Group Association. The opinions expressed in this paper do not necessarily reflect the opinions of the EuroQol Group, or those of the EuroQol Research Foundation. M Eugenia Socias and Bernard Le Foll report grants from Indivior, outside the work described in this paper. Didier Jutras-Aswad reports grants from the Canadian Institutes of Health Research and Health Canada, related to the work described in this paper; and non-financial support from Cardiol Rx and Tetra Bio Pharma, outside the work described in this paper. The remaining authors (Cassandra Mah, Emanuel Krebs, Benjamin Enns, and Bohdan Nosyk) declare they have nothing to disclose.