1. Department of Sociology, University of Colorado Boulder, Boulder, Colorado, USA.
2. University of Colorado Population Center, University of Colorado Boulder, Boulder, Colorado, USA.
3. Department of Sociology, Nuffield College, University of Oxford, Oxford, United Kingdom.
4. Leverhulme Centre for Demographic Science, University of Oxford, Oxford, United Kingdom.
5. College of Nursing, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.