Kules, BillShneiderman, BenPlaisant, CatherinePaired hierarchical visualizations (PairTrees) integrate treemaps, node-link diagrams, choropleth maps and other information visualization techniques to support exploration of hierarchical data sets at multiple levels of abstraction. This paper describes several novel applications of PairTrees in the econometric and health statistics domains, as well as some challenges and trade-offs inherent in the technique.en-USTechnical Report