I am the project director for the LinkageLibrary at ICPSR. LinkageLibrary is a repository for linkage code, data linkage results including databases, and literature using the data or code. In my own work I developed two large quantitative linked databases using progressive algorithms, one linking census and death records funded by NSF (9224572), and the other funded by NIH (R01 HD-044889-01) linking population and farm censuses cross-sectionally and longitudinally.