Survey Sample Design
The ACS is a new survey conducted by the U.S. Census Bureau. This survey uses a series of monthly samples to produce annually updated data for the same small areas (census tracts and block groups) as the decennial census long-form sample formerly surveyed. Initially, 5 years of samples are required to produce these small-area data. Once the Census Bureau has collected 5 years of data, new small-area data are produced annually.
Each month, the Census Bureau selects a systematic sample of addresses from the most current master address file (MAF). The sample represents the entire United States. No address will receive the ACS questionnaire more than once in any 5-year period. A larger proportion of addresses are sampled for small government units (American Indian reservations, counties, and towns). The monthly sample size is designed to approximate the sampling ratio of Census 2000, including the oversampling of small government units.
The ACS is a new approach to producing critical information about the characteristics of local communities. It will eliminate the need for a long form in the 2010 Census and is a key part of the Census Bureau's Decennial Census Program. The ACS publishes social, housing, and economic characteristics for demographic groups covering a broad spectrum of geographic areas in the United States and Puerto Rico.
The ACS shifted from a demonstration program with a different sample design and sample size to the full sample size and design in 2005. It became the largest household survey in the United States, with an annual sample size of about 3 million addresses. Every year the ACS can support the release of single-year estimates for geographic areas with populations of 65,000 or more. The ACS will accumulate samples over 3-year and 5-year intervals to produce estimates for smaller geographic areas, including census tracts and block groups.
Social characteristics. School enrollment, education, marital status, fertility, grandparents caring for children, veteran status, disability status, residence one year ago, place of birth, U.S. citizenship status, year of entry, world region of birth of foreign-born individuals, language spoken at home, relationship, households by type, and ancestry.
Economic characteristics. Employment status, commute to work, occupation, industry, class of worker, income and benefits, and poverty status.
Housing characteristics. Housing occupancy, units in structure, year structure built, number of rooms, number of bedrooms, housing tenure, year householder moved into unit, vehicles available, house heating fuel, utility costs, occupants per room, housing value, mortgage status and costs, and gross rent.
Demographic characteristics. Age, gender, race, and Hispanic origin.