1. All data collected from the project will eventually be deposited with the Inter-University Consortium for Political and Social Research (ICPSR) at the University of Michigan and will be available to interested scholars. We are grateful to Susan Carter, Thomas Dublin, Stanley Engerman, Gary Gerstle, Victoria MacDonald Huntzinger, Richard Murnane, Judith Singer, Daniel Scott Smith, Julie Juhon Sun, Stephan Thernstrom, Terrence Tivnan, and Maris Vinovskis for helpful comments. The project described in this paper has been funded by the Spencer Foundation and the National Science Foundation. Opinions expressed are our own and not those of the foundations
2. The One Best System
3. The work is not particularly arduous or time consuming because a large fraction of the population will have no occupation listed (for example, women and children not gainfully employed)