The American Community Survey (ACS) is an ongoing nationwide household survey conducted by the U.S. Census Bureau. The ACS collects and publishes data on social, economic, housing, and demographic characteristics of the population. The ACS creates period estimates, which represent characteristics over a specific data collection period.
There are two types of estimates available in the ACS:
1-year estimates available for geographic areas with populations of 65,000 or more
5-year estimates available for all geographic areas down to the census tract and block group levels.
This means that there are two main types of estimates (both 1-year and 5-year) available for areas with at least 65,000 people. The primary advantage of the 1-year estimates is data currency, while the primary advantage of the 5-year estimates is statistical reliability (especially for smaller population sub-groups).
Both types of estimates are released annually. Deciding which one better suits your needs involves balancing the need for currency with the increased statistical reliability that comes with the multi-year estimates.
We recommend using the coefficient of variation (CV), which is a measure of how reliable an estimate is, as a guide and suppressing any estimate with a CV greater than 35%. CV information is available in the table sections of the Tableau dashboard when you hover over an estimate and in downloads. When comparing 5-year estimates over time, it is important to compare non-overlapping timeframes (i.e., do not compare estimates from 2015-2019 and 2017-2021).
For more information on ACS data, visit the ACS handbook at: https://www.census.gov/programs-surveys/acs/library/handbooks/general.html
To obtain ACS data for other areas or topics, please use the Census Bureau’s CEDSCI tool at: https://data.census.gov/cedsci/advanced
The population for whom poverty status is determined excludes individuals in institutional group quarters (such as prisons or nursing homes), college dormitories, military barracks and unrelated individuals under age 15 (such as foster children).
Important Notice: The standard 1-year estimates from the 2020 ACS were not released because of the impacts of the COVID-19 pandemic on data collection. The Census Bureau released a series of “experimental” 2020 1-year estimates, but these are not available for all geographies and are not shown here. For more information on this topic, see https://www.census.gov/programs-surveys/acs/data/experimental-data.html.