1 Department of Sociology, University of Cambridge, United Kingdom; School of Social Sciences, University of Waikato, New Zealand. Electronic address: ths27@cam.ac.uk.
2 Department of Sociology, University of Oxford, United Kingdom; Department of Sociology, University of Amsterdam, The Netherlands.
3 Department of Sociology, University of Oxford, United Kingdom.
4 European Observatory on Health Systems and Policies, London School of Hygiene & Tropical Medicine, United Kingdom.
5 Department of Sociology, University of Cambridge, United Kingdom.