1. Center for Medicine, Health, and Society, Vanderbilt University, 300 Calhoun Hall, PMB #351665, 2301 Vanderbilt Place, Nashville, TN 27235, USA
2. Department of Population Health Sciences, Duke University, Durham, NC, USA
3. Population Research Institute, Duke University, Durham, NC, USA
4. Graduate School of Education, Stanford University, Stanford, CA, USA
5. Department of Sociology and Institute of Behavioral Science, University of Colorado at Boulder, Boulder, CO, USA
6. Department of Sociology, Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA