Why can I not view 2010 block group data for household and family income?
There are 5 sources of “2010” block group data for household and family income, none of which describe only 2010 characteristics, but rather, each summarizes characteristics across a 5-year period that includes 2010 (specifically, 2006-2010, 2007-2011, 2008-2012, 2009-2013, and 2010-2014). That’s because the data come from the [American Community Survey (ACS) 5-Year Data], the only source that provides this type of information for all block groups in the U.S. in recent years.
In the NHGIS Data Finder, you can find tables from the 5-year data sources by using a Years filter for a 5-year period, or by using a Datasets filter for an ACS 5-year dataset.
You may recall that it was previously possible to use only a “2010” single-year filter to find 5-year data tables. That changed in September when NHGIS changed how year filtering works in the Data Finder:
Previously, if a user selected a filter for any single year that was also the release year of American Community Survey (ACS) data, tables from the corresponding multi-year ACS dataset(s) would also appear in the “Select Data” listing. Now, only tables that report data for the specific selected year will appear.
There were various motivations for making this change. The most immediate motivation was that, after our last release of 2020 Census data (the 2020 DHC) in early September, we found users were still requesting 2016-2020 5-year ACS tables at a high rate relative to the corresponding 2020 Census tables, and we believed that it was more appropriate when users filtered on a single year to display only tables that provide data for that single year. After making the filtering change, the rates of use of 2020 Census tables went up greatly.
Note also that of all the 5-year periods that include the year 2010, the one that is likely to correspond best to the single year of 2010 is 2008-2012, which is centered on 2010, and not 2006-2010, which is the only 5-year period that used to appear when a “2010” Years filter was selected with the previous NHGIS filter behavior. This was another reason we made the change.