Empirical research by labor economists relies overwhelmingly on data collected in largescale, government funded surveys. The availability of such data dramatically lowers the cost of conducting research for any individual scholar. Large sample sizes and extensive breadth of variables allow precise testing of a wide variety of hypotheses. Combined with enormous increases in computing capabilities and the development of new techniques to analyze such data, these data sets have transformed the field of labor economics (James Heckman, 2000).

The use of large-scale survey data, however, has not come without a cost. The set of questions that can be addressed is constrained by the variables that have been collected. These studies are typically nationally representative, with sample sizes too small to undertake detailed analysis in particular localized geographic areas or very specific subsets of the overall …