[1] Grp Hlth Res Inst, 1730 Minor Ave,Suite 1600, Seattle, WA 98101 USA
[2] Univ Penn, Ctr Clin Epidemiol & Biostat, Dept Biostat & Epidemiol, 604 Blockley Hall,423 Guardian Dr, Philadelphia, PA 19104 USA
[3] Drexel Univ, Dornsife Sch Publ Hlth, Nesbitt Hall,3215 Market St,Room 335, Philadelphia, PA 19104 USA
[4] Univ Iowa, Dept Hlth Management & Policy, Coll Publ Hlth, 145 Riverside Dr,100 CPHB S153A, Iowa City, IA 52242 USA
[5] Univ Colorado, Ctr Canc, 13001 East 17th Pl,Campus Box F434, Aurora, CO 80045 USA