The US2010 Project supported by Russell Sage Foundation has developed a method to allow researchers to analyze census tract data with constant boundaries for the period 1970-2010. This method is advantageous especially for studies of change over time, when it is important to follow change within the same geographic area. The Longitudinal Tract Data Base (LTDB) is free at this URL: http://www.s4.brown.edu/us2010/Researcher/Bridging.htm. It uses the same GIS interpolation methods as the commercially available Neighborhood Change Data Base that scholars have used for 1970-2000. A significant feature is that users can import their own data (such as crime or health data for census tracts) and convert it themselves to 2010 boundaries. Soon it will include a capability to go in the other direction, converting 2010 data to 2000 boundaries.
John Logan, Brian Stults, Zengwang Xu