Response to Professor Olsen's commentary on 'random sampling - is it worth it?'.

Michael B. Bracken, Irva Hertz-Picciotto, Michael R. Elliott, Donald J. Dudley, Stephen Buka, James M. Robbins, Nigel Paneth School of Public Health School of Medicine, Yale University, New Haven, CT Department of Public Health Sciences, University of California, Davis, CA School of Public Health, University of Michigan, Ann Arbor Department of Epidemiology and Biostatistics Department of Pediatrics, Michigan State University, East Lansing, MI Department of Obstetrics and Gynecology, University of Texas Health Sciences Center, San Antonio, TX Department of Epidemiology, Brown University, Providence, RI Department of Pediatrics, University of Arkansas, Little Rock, AK