Housing Topics - Fact Sheet - Differences between the Vacancy Rate Estimates from the American Community Survey, the Current Population Survey/Housing Vacancy Survey, and the American Housing Survey

Differences between the Vacancy Rate Estimates from the American Community Survey, the Current Population Survey/Housing Vacancy Survey, and the American Housing Survey

When fully implemented, the American Community Survey (ACS) will be the largest household survey in the United States. Like the decennial census long form it is designed to replace, the ACS provides rental and homeowner vacancy rate estimates for small geographic areas – most cities, counties, and metropolitan areas of 250,000 or more during the testing phase, and, beginning in 2010, the ACS will use multi-year averages to provide estimates for all areas down to census tracts/block groups. Estimates for the nation and states are also available. All ACS estimates are updated annually.

The Current Population Survey/Housing Vacancy Survey (CPS/HVS) produces estimates of rental and homeowner vacancy rates each quarter for the United States, four census regions, states, and the 75 largest metropolitan areas (MAs).

The American Housing Survey (AHS) produces estimates of rental and homeowner vacancy rates for the United States, four census regions, and metropolitan areas in odd-numbered years. Estimates for 41 metropolitan areas from the metropolitan area sample are updated every 6 years, with the residents of 13 or 14 metropolitan areas interviewed in even-numbered years. Estimates for 6 metropolitan areas whose residents are interviewed with the national sample are updated every 4 years in odd-numbered years along with national and regional estimates.

This chart summarizes the key differences between the ACS, the CPS/HVS, and the AHS:

	American Community Survey	Current Population Survey/Housing Vacancy Survey	American Housing Survey
Principal Purpose	Replace the decennial census long form by providing annual (or multi-year average) estimates of selected social, economic, and housing characteristics of the population for many geographic areas and subpopulations.	Provide specific socioeconomic estimates for the United States and estimates for regions of selected characteristics and subpopulations. Provide timely estimates of the homeownership rate and rental and homeowner vacancy rates each quarter.	Provide a current and ongoing series of data on the size, composition, and state of housing in the United States and changes in the housing stock over time. Collect housing statistics that the U.S. Department of Housing and Urban Development (HUD) uses to evaluate and develop its federal housing programs.
Geography	Nation, states, counties, and places of 65,000 or more and Puerto Rico (beginning in 2005). Eventually, areas as small as census tracts/block groups using multi-year averages.	Nation, regions, states, and 75 largest metropolitan areas (which have a population of 600,000 or more).	Nation, regions, and 47 selected metropolitan areas with city and county subareas of at least 100,000 population.
Sample Size	About 800,000 addresses per year during the testing phase (2000-2004); about 3 million addresses per year when fully implemented in 2005. Data are collected from about one-twelfth of the sample each month.	About 71,000 addresses per month. A unit is in sample for 4 consecutive months, out for 8 months, back in sample for 4 months, and then retired from the sample.	About 56,000 addresses in each odd-numbered year. The National survey is longitudinal--each sample unit from the basic sample has been visited every other year since 1985. The AHS-Metropolitan sample is also longitudinal and consists of about 4,500 addresses per metropolitan area, with interviewing of a rotating set of 13 or 14 areas in even-numbered years.
Data Collection Method	Mail and computer-assisted telephone and personal-visit interviews. About half the responses are obtained by mail. Most vacant units are not identified until the third month of data collection (the first personal visit). In that month, a 1-in-3 subsample of all addresses for which responses have not been obtained are visited by field representatives. The ACS is a mandatory survey.	Computer-assisted telephone and personal visit interviews. All units in sample are visited if a telephone interview is not obtained. The CPS/HVS is a voluntary survey.	Computer-assisted telephone and personal-visit interviews. The AHS is a voluntary survey.
Residency Status	The ACS includes people at the address where they are at the time of the survey if they have been there or will be there more than two months, whether or not the people have a “usual residence elsewhere.”	The CPS/HVS includes people if they consider the unit to be their place of usual residence (where they spend most of the time during the year). If they have more than one home, the interviewer has to determine if the sample unit is their usual residence, that is, where they spend most of their calendar year.	Same as CPS/HVS.
Population Universe	In the testing phase and 2005, the ACS includes the household population. This universe includes both the civilian and military population in households and excludes the group quarters population. The ACS is expected to start including the group quarters populations (that is, the resident population) in 2006. The group quarters population consists of the institutionalized (such as people in correctional institutions or nursing homes) and the noninstitutionalized (most of whom are in college dormitories). The weighting is controlled to population estimates as of July 1 (e.g., July 1, 2003 for the 2003 ACS).	The CPS/HVS includes the civilian noninstitutionalized population. This universe includes civilians in households, people in noninstitutional group quarters (other than military barracks) and military in households living off post or with their families on post (as long as at least one household member is a civilian adult). The universe excludes other military in households and in group quarters (barracks), and people living in institutions. The weighting is controlled to independent counts of housing units for the month of the estimate.	The AHS includes occupied and vacant housing units and all people in housing units. The universe excludes all people in group quarters. The weighting is controlled to independent counts of housing units as of July 1 (e.g., July 1, 2003 for the 2003 AHS-National).
Time Period Covered	Monthly interviews are conducted and units are classified as of the day they are first contacted; nearly all vacant units in the ACS are not contacted until the third month of data collection.	Monthly interviews are conducted and information on the vacancy status of the unit are collected and processed as of the interview week, which is normally the week containing the 19^th of each month.	Interviews were conducted from June to September 2003 and classified by vacancy status as of the day they were first contacted, for the 2003 AHS-National.


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