Data from 2014-2018 are comparable to 2009-2013 as long as some caution is used. In 2010, there were two major changes to the coding rules. If up to two ancestries were listed, both were coded, even if one was the specific of the other or if one was American. Also, race groups and Hispanic groups were coded with the same priority as non-race and non-Hispanic groups. For example, "Haitian Black French" would previously have been coded Haitian and French, but now would be coded Haitian and Black.

Methodological changes to citizenship edits may have affected citizenship data for those born in American Samoa. Users should be aware of these changes when using 2018 data or multi-year data containing data from 2018. For more information, see: American Samoa Citizenship User Note.

Modest changes have been made to the region and country groupings. Specifically, in 2009 Macau (code 225) is now included under the definition of China, and Jan Mayen (code 121) and Svalbard (code 135) are included under the definition of Norway, please see 2009 ACS Code List.  On October 10, 2010 the Netherlands Antilles were dissolved, and for the 2011 ACS place of birth codes, Netherlands Antilles remains as code 336. Bonaire has been assigned new POB code 344, Curacao is 345, Saba is 346, Sint Eustatius is 347, and Sint Maarten is 348; please see the 2011 ACS Code List. For the 2014 ACS South Sudan (code 463) was added as an eligible place of birth, please see the 2014 ACS Code List. These changes do not limit comparing most 2009-2013 ACS 5-year and 2014-2018 ACS 5-year estimates.

Use caution when making comparisons between the 2009-2013 ACS 5-year estimates and 2014-2018 ACS 5-year estimates of spoken languages and English-speaking ability.  Some languages need additional steps for comparison. Please refer to the 2016 Language Data User Note for comparability guidance.

Income and earnings estimates in the 2009-2013 ACS 5-year data set are inflation-adjusted to 2013 dollars.  Income and earnings estimates in the 2014-2018 ACS 5-year data set are inflation-adjusted to 2018 dollars.  To compare income estimates between the two, multiply the 2009-2013 dollar estimates by 1.07970803 (CPI-U-RS) in order to inflation-adjust 2013 dollars to 2018 dollars. The exception is the Comparative Economic Characteristics Profile (CP03) where all income and earnings dollar values are presented in 2018 inflation-adjusted dollars. Note that the Census Bureau inflation-adjusts microdata to arrive at the adjusted dollar values in CP03.  Data users will not be able to exactly replicate the CP03 2009-2013 inflation-adjusted values.

Income and earnings estimates in the 2009-2013 ACS 5-year data set are inflation-adjusted to 2013 dollars.  Income and earnings estimates in the 2014-2018 ACS 5-year data set are inflation-adjusted to 2018 dollars.  To compare income estimates between the two, multiply the 2009-2013 dollar estimates by 1.07970803 (CPI-U-RS) in order to inflation-adjust 2013 dollars to 2018 dollars. The exception is the Comparative Economic Characteristics Profile (CP03) where all income and earnings dollar values are presented in 2018 inflation-adjusted dollars. Note that the Census Bureau inflation-adjusts microdata to arrive at the adjusted dollar values in CP03.  Data users will not be able to exactly replicate the CP03 2009-2013 inflation-adjusted values.

In 2013, the veteran status question was modified. As a result, we recommend using caution when comparing the 2014-2018 estimates to estimates from 2009-2013 of the veteran population or any earlier ACS 5-year data. For more information, visit the Veterans Statistics webpage.

In 2010, we added an instruction to the food stamp question incorporating the new program name - Supplemental Nutrition Assistance Program (SNAP).

The 2009 to 2013 ACS industry data was coded using the 2007 North American Industry Classification System (NAICS). The ACS industry data for 2013 to 2017 years was coded based on the 2012 revision of the NAICS codes. The 2018 ACS industry data and later years are based on the 2017 revision of the NAICS codes.

Because of the NAICS revisions and Census industry code changes, we recommend using caution when comparing 2014-2018 industry data with 2009-2013 industry data. For more information on Census industry code changes, please visit the Industry and Occupation website.

The Census occupation codes for 2018 and later years are based on the 2018 revision of the Standard Occupational Classification (SOC). To allow for the creation of 2004-2018 tables, occupation data for data years 2014-2017 in the multiyear file was recoded to 2018 Census occupation codes. Therefore, the 2009-2012 and 2014-2018 occupation data are not comparable. For more information on the Census occupation code changes, please visit Industry and Occupation website.

Data was not available prior to 2013.  Therefore, the 2009-2013 ACS 5-year estimates were not available.  For more information about computer and internet use questions in the ACS and other Census Bureau surveys, visit the Computer and Internet Use website.

Data was not available prior to 2014.  Therefore, the 2009-2013 ACS 5-year estimates were not available. The 2014-2018 ACS 5-year estimates provide the first time 5-year estimates are available for this topic.