1 Nivel (Netherlands Institute for Health Services Research), Utrecht, the Netherlands; Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Primary and Community Care, Nijmegen, the Netherlands; Faculty of Caring Science, Work Life and Social Welfare, University of Borås, Borås, Sweden. Electronic address: S.vanDulmen@nivel.nl.
2 Centre for Health and Technology Faculty of Health and Social Sciences, University of South-Eastern Norway, Drammen, Norway.
3 Patient Education and Counseling and Department of Behavioural Medicine University of Oslo, Norway.