Documentation
Full survey documentation is available here.
Notes
The data reported here for the 2010 Census may not exactly match the data as originally reported in 2010. To make the 2010 data comparable and place it on the 2020 boundaries the 2010 block population and characteristics were allocated to the 2020 blocks. The 2010 data were then aggregated to the 2020 geographies. Because of this the population and characteristics may be different than those reported officially by the Census Bureau in 2010. There are several reasons for this 1) Some of the boundaries were redrawn due to annexation or in some case remapping and correction of the previous boundaries; 2) The data allocation was based upon the land area occupied so there may be some slight differences injected because of that.
This method does make it possible to directly compare at various levels of geography the changes between 2010 and 2020 because it uses the same areas. Among the areas that officially changed boundaries between the 2010 and 2020 Census were most of the blocks, tracts, and block groups, as well as some counties, minor civil divisions and places. Except for annexation, remapping and other changes in the actual geography of the areas, the other differences are minor.
You should also note that the 2020 data has had noise injected into it because of the Census's new Disclosure Avoidance System (DAS). This can mean that population counts and characteristics, especially when they are particularly small, may not exactly correspond to the data as collected. As such caution should be exercised when examining areas with small counts. Ron Jarmin, acting director of the Census Bureau posted a discussion of the redistricting data, which outlines what to expect with the new DAS. For more details on accuracy you can read it here. https://www.census.gov/newsroom/blogs/director/2021/07/redistricting-data.html
