Stefan A Lipman1, Liying Zhang2, Koonal K Shah3,4,5, Arthur E Attema2. 1. Erasmus School of Health Policy & Management, Erasmus University Rotterdam, Rotterdam, The Netherlands. lipman@eshpm.eur.nl. 2. Erasmus School of Health Policy & Management, Erasmus University Rotterdam, Rotterdam, The Netherlands. 3. National Institute for Health and Care Excellence, London, UK. 4. School of Health and Related Research, University of Sheffield, Sheffield, UK. 5. PHMR Ltd, London, UK.