The USPS Vacancy Data provides quarterly aggregate data on addresses identified by the USPS as having been "vacant" or "no-stat" in the previous quarter. HUD is making these data available for researchers and practitioners to explore their potential utility for tracking neighborhood change on a quarterly basis. The potential power of these data is that they represent the universe of all addresses in the United States and are updated every three months. Under the agreement with the USPS, HUD can make the data available publicly at the Census Tract level provided users agree to the terms and conditions of the sublicense.
The USPS is reporting to HUD for each quarter the number of days an address has been in each category. Because USPS did not start counting days in each category until after entering into this agreement with HUD, the starting point for counting days in each category is November 18, 2005. So, for example, our December 2005 extract shows no addresses being on the vacant list for longer than three months because we had only been counting for just over a month. We will not know about addresses on the vacant list for longer than three years until the December 2008 extract.