1. Institute for Advanced Study in Toulouse, University of Toulouse 1 Capitole, Toulouse, France
2. Department of Sociology, University of Zürich, Zurich, Switzerland
3. Leverhulme Centre for Demographic Science, Department of Sociology, and Nuffield College, University of Oxford, Oxford, UK
4. Department of Sociology, University of Groningen, Groningen, the Netherlands
5. Nuffield College, University of Oxford, Oxford, UK