I am working on building a synthetic population that includes group quarters and am stumped by a pretty large inconsistency between the ACS 5-year and decennial census reported group quarter populations in the block group that contains the Cook County Jail in Chicago (block group 170318435001). The ACS 5-year estimates for the group quarter population in this block group hover around 9k in 2019, 2020, 2021, and 2022. However, the decennial 2020 estimate is only around 5k. The current Cook County Jail population is listed around 6k (https://www.cookcountysheriffil.gov/wp-content/uploads/2024/03/CCSO_BIU_CommunicationsCCDOC_v1_2024_03_08.pdf).
Wondering if anyone has any idea why this discrepancy could be so large? I am looking at table B09019 for ACS and the 2020 Census Redistricting Data (P.L. 94-171) Summary Files (P5) (https://www.census.gov/programs-surveys/decennial-census/about/rdo/summary-files.html#P1).
Appreciate any input!