ACS Data Users Group

Hello,

My grant manager gave me the raw data from the ACS 5-year estimates for low to moderate-income populations. Since there are no locators in the data, I am having difficulty plotting out the areas on ArcGIS. I have updated layers for both census tracts and block group boundaries. I joined the spreadsheet to each layer but Geoids don't fully match up for the tracts or they match up for the block groups but I can't filter the data only to show certain percentages. Does anyone else work with the ACS data for CDBG programs? Are you also having difficulty? any information would be beneficial.

thanks in advance.

Are you saying the data do not have a geoid when you say "locators"? What vintage are the ACS data? What vintage are your shapefiles?

the Geoid is just a combination of the state, county, tract and block group identifiers. The ACS data is from the ACS 5 year estimate, 2016-2020 and I downloaded the shapefiles from the HUD website today. Its updated tract and block group boundaries

You're likely using newer, mismatched shapefiles to older data. You'll either need to find newer data or older shapefiles--my best guess. What is vintage of those HUD shapefiles?

the tract and block group boundaries were updated in July. If the last year of the data is 2020, should I find shapefiles from 2020?

2016-2020 ACS would use shapefile created before 2020 to best of knowledge. 2016-2020 ACS was using 2010-based geo boundaries.

I may be wrong about 2016-2020 using 2010-based. Im hoping someone else chimes in. You can test by finding an older shapefile and seeing if your ACS geoids match with older shapefiles geo ids via its attribute table.

The Census Bureau has a nice resource showing the Vintage of Geographic Areas for ACS Estimates that have been released each year:

https://www.census.gov/programs-surveys/acs/geography-acs/geography-boundaries-by-year.2020.html#list-tab-626530102

For the 2020 estimates, there are a few geographies that used 2010 boundaries (PUMAs, Urban Areas, ZCTAs), but block groups were based on 2020 boundaries.

However, I don't work with CDBG program data so I can't speak to the mismatch with the ACS.