U.S. Census American Community Survey (ACS)


The Census American Community Survey (ACS) is an ongoing survey that provides data every year, giving communities the current information they need to plan investments and services. In the past, the decennial census consisted of a short form and a long form. In the 2000 Census, which was the last decennial census year in which the long form was conducted, it was sent to 1 in 6 households. The data was used to count additional details of the population such as income and education. Information from the ACS replaces the long form of the decennial census that was discontinued after the 2000 Census. As a result, demographic, socio-economic, and housing data are released every year rather than every ten years. Even though data are gathered and released every year, it is still part of the official census, and thus, participation is mandatory under federal law.

The ACS generates data that help determine how more than $400 billion in federal and state funds are distributed each year. Data from the ACS include the characteristics covered in the 2010 Census as well as additional items such as income and benefits, poverty, languages spoken, health insurance, education, employment, veteran status, disabilities, commute information, housing costs and more.

There are two different types of ACS datasets available and choosing which dataset involves more than simply considering the population size in your area. You must think about the balance between currency and sample size/reliability/precision.

For details, research implications, and examples, see “Understanding and Using ACS Single-Year and Multiyear Estimates,” page 39 in the General Data Users Handbook

Distinguishing features of ACS 1-year and 5-year estimates

1-year estimates 5-year estimates
12 months of collected data 60 months of collected data
Data for areas with populations of 65,000+ Data for all areas down to the Census Block Group level
Smallest sample size Largest sample size
Best when used Best when used
Currency is more important than precision Precision is more important than currency
Analyzing large populations Analyzing very small populations
  Examining tracts and other smaller geographies because 1-year estimates are not available