[1] Univ Oxford, Nuffield Dept Primary Care Hlth Sci, Oxford, England
[2] Univ Pompeu Fabra, Dept Business, TecnoCampus, Barcelona, Spain
[3] Univ Pompeu Fabra, Ctr Res Hlth & Econ CRES, Barcelona, Spain
[4] Erasmus Univ, Erasmus Sch Econ, Rotterdam, Netherlands
[5] Tinbergen Inst, Amsterdam, Netherlands
[6] Univ Pompeu Fabra, Dept Econ & Business, Barcelona, Spain