American Community Survey
The American Community Survey (ACS) is an annual survey operated by the Census Bureau to establish demographic information about the nation's population.
Usage
See here for notes on the public use microdata.
Design
Frequency
The ACS is administered annually, with continuous data collection. No household is sampled more than once in 5 years.
1-year estimates are usually published in the fall, and 5-year estimates are usually published in the winter.
Geographies
1-year estimates are published for geographic areas with populations of 65,000 or more. This threshold is set so that estimates can be made available for all states, territories, congressional districts, PUMAs, CBSAs, cities, and Native American areas.
5-year estimates are published for geographic areas with much smaller population levels. This includes ZCTAs, census tracts, and census block groups.
History
The ACS was launched in 2005 as a replacement for the long-form U.S. census. It provides more timely data because data collection is continuous, and then published in a periodic aggregation. It is used to allocate federal and state funding.