1. Center for Evidence-based Medicine, School of Public Health; Brown University; Providence RI USA
2. Department of Health Services, Policy & Practice, School of Public Health; Brown University; Providence RI USA
3. Department of Quantitative Health Sciences; University of Massachusetts Medical School; Worcester MA USA
4. Consulting Statistician; Sudbury MA USA
5. Office of Portfolio Analysis; National Institutes of Health; Bethesda MD USA
6. Research Design Center/Biostatistics Research Center, Clinical and Translational Science Institute; Tufts University, and Institute for Clinical Research and Health Policy Studies, Tufts Medical Center; Boston MA USA
7. Department of Biostatistics, School of Public Health; Brown University; Providence RI USA