1. G Jamtvedt, PT, MPH, is Researcher, Norwegian Centre for the Health Services, PO Box 7004, St Olavs Plass, N-0130 Oslo, Norway
2. KT Dahm, PT, MSc, is Research Assistant, Norwegian Centre for the Health Services
3. A Christie, PT, MSc, is Research Fellow, National Resource Centre for Rehabilitation in Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
4. RH Moe, PT, is Research Fellow, National Resource Centre for Rehabilitation in Rheumatology, Diakonhjemmet Hospital
5. E Haavardsholm, MD, is Research Fellow, Department of Rheumatology, Diakonhjemmet Hospital
6. I Holm, PT, PhD, is Professor, Rikshospitalet University Hospital/University of Oslo, Oslo, Norway
7. KB Hagen, PT, PhD, is Researcher, National Resource Centre for Rehabilitation in Rheumatology, Diakonhjemmet Hospital