1. Department of Biostatistics and Medical Informatics, University of Wisconsin, 600 Highland Avenue, Box 4675, Madison, WI 53792-4675, USA;
2. University of Washington, Seattle, WA, USA
3. GlaxoSmith Kline, King of Prussia, PA, USA
4. San Francisco VA Medical Center, San Francisco, CA, USA
5. University of Pittsburgh, Pittsburgh, PA, USA
6. Hogan & Hartson L.L.P, Washington, DC, USA
7. Statistics Collaborative, Washington, DC, USA
8. Human Genome Sciences, Inc., Rockville, MD, USA
9. Duke Clinical Research Institute, Durham, NC, USA