Jagpreet Chhatwal1, Maarten J Postma2. 1. Institute for Technology Asssessment, Massachusetts General Hospital, Harvard Medical school, Boston, MA, USA. Electronic address: jagchhatwal@mgh.harvard.edu. 2. Department of Health Sciences, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands and Department of Economics, Econometrics & Finance, University of Groningen, Faculty of Economics & Business, Groningen, The Netherlands.