1 Center for Evidence-based Practice, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA.
2 Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA. craig.umscheid@uphs.upenn.edu.
3 Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
4 Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.