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US Census and American Community Survey

Information on the US Census, American Community Survey: History, data, mapping, and more.



This page has information about the American Community Survey (ACS), an ongoing and continuous survey since 2005 that replaced the decennial census long form as the collection device for more detailed information about the US population than the standard decennial census.

The page has the following learning objectives:

  • Compare the differences between the United States Decennial Census and the American Community Survey
  • Understand the methodology of data collection and what that means for scholarly research
  • Interpret margin of error in ACS data
  • Determine whether 1-, 3-, or 5-year summary ranges are appropriate for your research

The American Community Survey

The American Community Survey

The American Community Survey (ACS) is an ongoing survey that provides vital information on a yearly basis. Information from the survey generates data that help determine how more than $675 billion in federal and state funds are distributed each year. [source]

Every year, the Census Bureau contacts over 3.5 million households across the country to participate in the ACS using a random sample of addresses. The information is used by government agencies, nongovernmental organizations, planners, tribal governments and organizations, businesses, researchers, journalists, and the public. [source]

Those already familiar with the US Census may recall that during the 20th century the questions were divided between a short form and a long form, where the short form asked basic questions about age, sex, race, and key housing questions. The long form asked more detailed questions but was only required of a subset of households. The 2010 decennial census used only the short form and the long form was replaced by the ACS. [source]

Check out the first couple minutes of the video below to get a broad overview of the ACS. Watch the whole thing to get an introduction to topics such as survey ranges and census geographies.

ACS vs. Census

  1. Single point in time (April 1st) vs a range of time (1 year, 3 years, 5 years)
  2. Enumeration vs Survey

Survey methodology

Margin of Error

Summary Ranges