The 2010 American Community Survey (ACS) estimates of vacant housing units (HUs) differ markedly from the counts of vacant housing units from the 2010 Census. Differences between the ACS housing unit sampling frame and the 2010 Census address list is one potential factor that may have contributed to the difference in the occupied and vacant housing unit classifications between ACS and the 2010 Census (Griffin, 2011).

The goal of this report is to examine and document the differences between the 2010 Census universe of housing units and the 2010 ACS housing unit sampling frame. The results of this project will not necessarily uncover the cause of the difference in the vacancy rates but will lead to a better understanding of the differences between the universes of housing units in the 2010 Census and 2010 ACS that might have contributed to differences in the vacancy rates.