Editing American Community Survey (section)

==Data availability==
[[File:Sample ACS data table.png|thumb|An American Community Survey data table sample]]

The Census Bureau aggregates individual ACS responses, also known as [[Microdata (statistics)|microdata]], into estimates at many [[:Category:United States Census Bureau geography|geographic summary levels]]. Among these summary levels are legal and administrative entities such as [[U.S. state|states]], [[County (United States)|counties]], [[Place (United States Census Bureau)#Incorporated place|cities]], and [[List of United States congressional districts|congressional districts]], as well as statistical entities such as [[metropolitan statistical area]]s, [[census tract|tracts]], [[census block group|block groups]], and [[census designated place]]s. Estimates for [[census block]]s are not available from ACS.<ref name=":2">{{cite web|title=Areas Published|url=https://www.census.gov/programs-surveys/acs/geography-acs/areas-published.html|website=Census.gov|access-date=July 31, 2015|author=United States Census Bureau}}</ref> [[Puerto Rico]] is the only US territory that is part of the ACS program.<ref name="ACS_Aug30"/>

In order to balance geographic resolution, temporal frequency, statistical significance, and respondent privacy, ACS estimates released each year are aggregated from responses received in the previous calendar year or the previous five calendar years. The Census Bureau provides guidance for data users about which data set to use when analyzing different population and geography sizes.<ref>{{cite web|author=United States Census Bureau|title=When to Use 1-Year, 3-Year or 5-Year Data|url=https://www.census.gov/programs-surveys/acs/guidance/estimates.html|website=www.census.gov|access-date=May 24, 2017}}</ref>

From 2007 to 2013, three-year estimates were available for areas with 20,000 people or more. This data product was discontinued in 2015 due to budget cuts.<ref>{{cite web|title=The ACS 3-year Demographic Estimates Are History|url = http://apdu.org/2015/02/03/the-acs-3-year-demographic-estimates-are-history/|website=APDU: The Association of Public Data Users|access-date=July 31, 2015|last=Poole|first=Ken| date=February 3, 2015 }}</ref> The last 3-year release was the 2011–2013 ACS 3-year estimates.

Current data releases include:
* '''1-year estimates''' are available for areas with a population of at least 65,000 people. The 2015 ACS 1-year estimates were released in 2016 and summarize responses received in 2015 for all states but only 26% of [[County (United States)|counties]] due to the 65,000 minimum population threshold.<ref name=":2" /> This is most suitable for data users interested in shorter-term changes at medium to large geographic scales.
* '''Supplemental estimates''' are shown in annual tables summarizing populations for geographies with populations of 20,000 or more.<ref>{{cite web|author=United States Census Bureau|title=American Community Survey Supplemental Data|url=https://www.census.gov/data/developers/data-sets/ACS-supplemental-data.html|website=www.census.gov|access-date=May 24, 2017}}</ref>
* '''5-year estimates''' are available for areas down to the [[Census block group|block group]] scale, on the order of 600 to 3000 people. The 2015 ACS 5-year estimates, summarizing data from 2011 to 2015, were released in 2016.<ref name=":2" />

Over the past decade, the American Community Survey has collected and supplied all data at local levels. This was a large breakthrough in the survey because it allows American citizens more individualized data on a community level as opposed to extrapolating from data collected over a larger area. It has also provided unparalleled information to be more accessible for local government planning and financing. Many conclusions for local data are averaged from various information across the area, but it is not always an adequate representation.<ref>{{Cite journal|last1=Spielman|first1=Seth|last2=Singleton|first2=Alex|date=September 3, 2015|title=Studying Neighborhoods Using Uncertain Data from the American Community Survey: A Contextual Approach|journal=Annals of the Association of American Geographers|volume=105|issue=5|pages=1003–1025|doi=10.1080/00045608.2015.1052335|doi-access=free}}</ref>

ACS estimates are available via a number of online data tools.<ref>{{cite web|title=Data Tools Chart|url =https://www.census.gov/programs-surveys/acs/guidance/which-data-tool/data-tools-chart.html|website=Census.gov|access-date=July 31, 2015|author=United States Census Bureau}}</ref> [https://www.census.gov U.S. Census website] (AFF) is the primary tool for disseminating ACS data, allowing users to drill down to specific tables and geographies (starting with 2013 estimates, AFF also includes block group data). A selection of the most popular tables is shown in [https://www.census.gov/quickfacts/ QuickFacts]. Other tools include [http://onthemap.ces.census.gov/em/ OnTheMap for Emergency Management], [https://www.census.gov/data/data-tools/cbb.html Census Business Builder] and [https://census.gov/mycd/ My Congressional District]. [https://www.census.gov/tribal/ My Tribal Area] featuring 5-year estimates for federally recognized tribes, launched in 2017. The Summary File is the most detailed data source and is available as a series of downloadable text files or through an [[application programming interface]] (API) for software developers.

Custom cross-tabulations of ACS questions can be made using the [https://www.census.gov/programs-surveys/acs/technical-documentation/pums.html Public Use Microdata Sample] (PUMS), freely accessible through the [https://www.census.gov/programs-surveys/acs/data/pums.html Census Bureau website] and [[Integrated Public Use Microdata Series]]. PUMS data contain responses to every question from a sample of respondents. To protect respondent privacy, PUMS data are [[Data anonymization|anonymized]] and only available down to areas containing 100,000 people or more known as [[Public Use Microdata Area]]s (PUMAs).<ref>{{cite web|title=About PUMS|url=https://www.census.gov/programs-surveys/acs/technical-documentation/pums/about.html|website=Census.gov|access-date=July 31, 2015|author=United States Census Bureau}}</ref> The analysis of all ACS microdata without the sampling and anonymization in PUMS is restricted to qualified researchers at secure Federal Statistical Research Data Centers (FSRDCs).<ref>{{cite web|title=Federal Statistical Research Data Centers|url=https://www.census.gov/fsrdc|website=Census.gov|access-date=August 11, 2015|author=United States Census Bureau}}</ref>