Validation of algorithms in studies based on routinely collected health data: general principles

principles 4 Vera Ehrenstein, MPH, DSc, Maja Hellfritzsch, MD, PhD, Johnny Kahlert, PhD, Sinéad M 5 Langan, FRCP, MSc, PhD, Hisashi Urushihara, MSc, DrPH, Danica Marinac-Dabic, MD, PhD, 6 MMSc, FISPE, Jennifer L Lund, PhD, Henrik Toft Sørensen, MD, PhD, DMSc, DSc, Eric I 7 Benchimol, MD, PhD 8 Corresponding author: Dr. Vera Ehrenstein, Department of Clinical Epidemiology, 9 Department of Clinical Medicine, Aarhus University, Olof Palmes Allé 43-45, Aarhus N, 10 Denmark, ve@clin.au.dk 11 Author affiliations: 12