2024-03-28T18:41:27
141121
Thu Mar 28 18:41:29 EDT 2024
Historic Redlining Scores for 2010 and 2020 US Census Tracts
Helen C.S. Meier
Bruce C. Mitchell
141121
https://doi.org/10.3886/E141121V2
2021-10-15
The Home Owners’ Loan Corporation (HOLC) was a U.S. federal agency
that graded mortgage investment risk of neighborhoods across the U.S. between
1935 and 1940. HOLC residential security maps standardized neighborhood risk appraisal
methods that included race and ethnicity, pioneering the institutional logic of
residential “redlining.”
The Mapping Inequality Project digitized the HOLC mortgage
security risk maps from the 1930s. We overlaid the HOLC maps with 2010 and 2020 census tracts for 142
cities across the U.S. using ArcGIS and determined the proportion of HOLC
residential security grades contained within the boundaries. We assigned a numerical value to each HOLC risk category as
follows: 1 for “A” grade, 2 for “B” grade, 3 for “C” grade, and 4 for “D”
grade. We calculated a historic redlining score from the summed proportion of
HOLC residential security grades multiplied by a weighting factor based on area
within each census tract. A higher score means greater redlining of the census
tract. Continuous historic redlining score, assessing the degree of
“redlining,” as well as 4 equal interval divisions of redlining, can
be linked to existing data sources by census tract identifier allowing for one
form of structural racism in the housing market to be assessed with a variety
of outcomes. The 2010 files are set to census 2010 tract boundaries. The 2020 files use the new census 2020 tract boundaries, reflecting the increase in the number of tracts from 12,888 in 2010, to 13,488 in 2020. Use the 2010 HRS with decennial census 2010 or ACS 2010-2019 data. As of publication (10/15/2020) decennial census 2020 data for the P1 (population) and H1 (housing) files are available from census.
Structural racism
redlining
United States Metro Areas