Frequently Asked Questions

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When is it best to use American Community Survey (ACS) 1-year, 3-year, or 5-year estimates?

The primary consideration is population size:

  • 1-year estimates are available for areas with populations of 65,000 or more
  • 1-year supplemental estimates are available for areas with populations of 20,000 or more
  • 3-year estimates are no longer produced but are available for 2011-2013 and earlier, for populations of 20,000 or more
  • 5-year estimates are available for all areas

You must also think about the balance between currency and sample size/data quality. The 1-year estimates are more current than the 5-year estimates. However, the 5-year estimates have a larger sample size and are therefore usually more precise than the 1-year estimates. The increased precision of a 5-year estimate may be particularly important if you are studying a small area or a small population subgroup.

For more detailed information, visit When to use 1-year, 3-year, or 5-year estimates on the American Community Survey (ACS) website.

  • ACS 3-year estimates have been discontinued. The 2005-2007, 2006-2008, 2007-2009, 2008-2010, 2009-2011, 2010-2012 and 2011-2013 ACS 3-year estimates will remain available to data users, but no new 3-year estimates will be produced. Every community in the nation will continue to receive a detailed statistical portrait of its social, economic, housing, and demographic characteristics through 1-year and 5-year ACS products.
  • ACS 1-year 2014 Supplemental Estimates consist of 58 detailed tables tabulated on the 1-year microdata for geographies with populations of 20,000 or more. These supplemental estimates were released on American FactFinder (AFF) and the API on July 21, 2016, and are available for the same geographic summary levels as those in the ACS 1-year dataset.


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