Background on Analysis The analysis of long-term vacancy by neighborhood is based on data collected by the U.S. Postal Service (USPS). The Department of Housing and Urban Development (HUD) processes the data and makes statistics by census tract available to researchers at government and non-profit institutions. Details can be found at www.huduser.org/portal/datasets/usps.html.
The first step is to identify census tracts with a large fraction of long-term vacant housing units. Because an address could appear to be vacant if it is seasonally occupied, we drop census tracts with a share of seasonal housing units greater than 10 percent (data on seasonal housing units by census tract are from the 2006–10 American Community Survey).