A recently launched online mapping tool allows users to display and download Census data for states, cities, counties and neighborhoods that indicate how difficult it might be to count the people living in those areas in the 2010 Census.

The interactive site is derived from the Census Bureau’s hard-to-count database, which assembles a dozen housing, demographic and socioeconomic variables that were correlated with poor response rates in the 2000 Census. Those indicators include the poverty rate, share of households where English is not spoken very well, and proportion of homes that are rented.

The site, developed by researchers at the City University of New York with foundation funding, allows users to display these indicators for each level of geography down to the census tract, a neighborhood unit of about 4,000 people. For each census tract, users can access the Census Bureau’s “hard-to-count score,” which is a summary measure based on the hard-to-count variables, as well as the 2000 Census mail return rate for each area and additional demographic data.

This tool is intended to help local governments and Census Bureau partner organizations target their efforts to promote participation in the 2010 Census by focusing on areas where outreach is needed. The data also can be of use to researchers, journalists and others seeking information about these areas.