1. Nam Hee Choi is Lecturer, Department of Statistics, University of Michigan, Ann Arbor, MI 48109. William Li is Professor, Carlson School of Management, University of Minnesota, Minneapolis, MN 55455. Ji Zhu is Associate Professor, Department of Statistics, University of Michigan, Ann Arbor, MI 48109 . We thank Rayjean Hung, Stefano Porru, Paolo Boffetta, and John Witte for sharing the bladder cancer dataset. Choi and Zhu are partially supported by grants DMS-0705532 and DMS-0748389 from the National...