Variables, and the values they represent, may change over time. Use this 2020 5YR API Changes document as a guide for which variables have changed from the prior year for 2020 ACS 5-Year Detailed Tables, Data Profiles and Subject Tables. See below for a description of each change type.
For table changes, check the ACS product changes webpage for source table changes.
The 2016-2020 ACS 5-year data products that report data related to Congressional Districts are based on the 116th Congress. The Census Bureau does not collect congressional district boundaries from the states during the congressional session that aligns with the decennial census (e.g., 117th). Additional explanation can be found in our geographic user note.
In September 2016, ACS released annotation variables that return character representations of each estimate. Many annotations return as null. However, if an annotation variable returns a value, it provides important information about the estimate or margin of error. For example, if an estimate variable (variable ending in “E”) returns “-888888888”, the annotation variable will return “(X)”. Looking at the Notes on ACS Estimates and Annotation Values, this means the estimate is not applicable or not available. For a complete list of return values and their annotations, see Notes on ACS Estimates and Annotation Values.