The dangers of conditioning on the time of occurrence of one demographic process in the analysis of another
Demographers and others often study the interaction between two types of individual-level behaviour, such as migration and childbearing. Unfortunately, one can get estimation bias if one compares childbearing before and after migration from data confined to migrants, say, as is sometimes done to see whether international migration disrupts fertility. Similar issues can arise in comparisons of union formation before and after first birth, marriage formation before and after home purchase, as well as in other comparisons of behaviour before and after an index event if one confines the study only to those who have experienced the index event. We point out that if one does this, then the study of behaviour before the index event actually conditions on the later arrival of the index event. This amounts to anticipatory analysis, which normally produces an estimation bias. In this paper we discuss this issue, provide a mathematical and graphical representation of it, and show how one can avoid estimation bias and get a meaningful (unconditional) comparison of behaviour before and after the index event provided the data contain enough information for both sub-periods.
|Date of creation:||May 2013|
|Date of revision:|
|Contact details of provider:|| Web page: http://www.demogr.mpg.de/|
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Hill Kulu & Andres Vikat, 2007. "Fertility differences by housing type: an effect of housing conditions or of selective moves?," MPIDR Working Papers WP-2007-014, Max Planck Institute for Demographic Research, Rostock, Germany.
- Marta Roig Vila & Teresa Castro-Martín, 2007. "Childbearing Patterns of Foreign Women in a New Immigration Country. The Case of Spain," Population (english edition), Institut National d'Études Démographiques (INED), vol. 62(3), pages 351-379.
- Courgeau, Daniel & Lelievre, Eva, 1993. "Event History Analysis in Demography," OUP Catalogue, Oxford University Press, number 9780198287384, March.
- Jan M. Hoem & Lesia Nedoluzhko, 2008. "Marriage formation as a process intermediary between migration and childbearing," MPIDR Working Papers WP-2008-015, Max Planck Institute for Demographic Research, Rostock, Germany.
- Gunnar Andersson & Boris Sobolev, 2001. "Small effects of selective migration and selective survival in retrospective studies of fertility," MPIDR Working Papers WP-2001-031, Max Planck Institute for Demographic Research, Rostock, Germany.
- Laura E. Hill & Hans P. Johnson, 2004. "Fertility Changes Among Immigrants: Generations, Neighborhoods, and Personal Characteristics," Social Science Quarterly, Southwestern Social Science Association, vol. 85(3), pages 811-827.
- Jan M. Hoem & Lesia Nedoluzhko, 2008. "Marriage formation as a process intermediary between migration and childbearing," Demographic Research, Max Planck Institute for Demographic Research, Rostock, Germany, vol. 18(21), pages 611-628, June.
When requesting a correction, please mention this item's handle: RePEc:dem:wpaper:wp-2013-006. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Peter Wilhelm)
If references are entirely missing, you can add them using this form.