1. Office of Analysis and Epidemiology, National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland.
2. Health Services and Economics Branch, Division of Cancer Control and Population Sciences, National Cancer Institute, Rockville, Maryland.
3. Applied Cancer Screening Research Branch, Division of Cancer Control and Population Sciences, National Cancer Institute, Rockville, Maryland.
4. Division of Health Promotion and Behavioral Science, The University of Texas-Houston, School of Public Health, Houston, Texas.