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Decennial Census and American Community Survey (ACS)

The Decennial Census and the American Community Survey (ACS) are part of the Decennial Census Program of the U.S. Census Bureau. Since 2005, in order to provide communities, businesses and the public with detailed information more frequently, data that were historically collected only once every 10 years by the decennial census long form have been collected monthly (and released annually) through the ACS.

Collecting Additional Information Since 1790

The U.S. Constitution states that a census “shall be made within three years after the first meeting of the Congress of the United States, and within every subsequent term of ten years, in such manner as they shall by law direct.” Congress passed separate laws for each decennial census and specified the information to be collected. In 1954, Congress codified earlier census acts and all other statutes authorizing the decennial census as Title 13, U.S. Code.

In the 20th century, most addresses received a “short” form, while a portion of addresses received a more detailed “long” form. The Census 2000 short form was designed to collect basic demographic and housing information (such as age, race, sex, relationship, and tenure) to be used for apportionment and redistricting. The long form, sent to approximately 1 in 6 households, collected social, housing, and economic information (such as citizenship, educational attainment, disability status, employment status, income, and housing costs) that was used to plan and determine funding for a wide array of federal, state, local, and tribal programs.

Collecting Information throughout the Decade

In the early 1990s, demands for timely, nationally consistent statistics led federal government policymakers to consider the feasibility of collecting long form data continuously throughout each decade. The benefits of providing recent stats, along with the anticipated decennial census benefits in cost savings, planning, improved coverage, and more efficient operations, led the Census Bureau to pursue continuous measurement, later called the American Community Survey (ACS). After years of testing, outreach to stakeholders, and interaction with key data users—especially those in the statistical and demographic communities—the bureau launched the ACS in 2005.

This innovation enabled the 2010 Census to be a “short form only” census. Decoupling the collection of short and long form data allowed the U.S. Census Bureau to focus decennial census efforts on the constitutional requirements to produce a count of the resident population, while employing technology in both collections to improve efficiencies, improve accuracy, and reduce costs. The result has been the dissemination of more current and detailed information than has ever been available.

The ACS Compliments the Decennial Census

The 2020 Decennial Census program, comprised of the 2020 Census and the ACS will provide an official count through a “short form only” census, as well as a portrait of communities counted across the nation through data collected by the ACS. This program is the only data-gathering effort that collects information from enough people to produce comparable data for every geographic area recognized by the Census Bureau.

Page Last Revised - November 23, 2021
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