Historic redlining, structural racism, and firearm violence: A structural equation modeling approach

Abstract

Background: Firearm homicides disproportionately affect Black communities. Redlining - discriminatory lending practices of the early 20^th century - are associated with current increased rates of firearm violence. Poverty and concentrated disadvantage are also associated with firearm violence. The interaction of these factors with racist redlining housing practices remains unclear.

Methods: We used generalized structural equation modeling to characterize the mediators through which redlining practices of the 1930s led to present rates of firearm violence in Boston using a negative binomial model. Principle component analysis was used to create four distinct mediating variables representing census block socioeconomic and built environment information, while reducing dimensionality. We calculated the direct effect between harmful (Red and Yellow) vs beneficial (Green) designations and firearm incident rate, indirect effect between redlining designation and firearm incident rate through each mediating variable, and the total effect. The percentage mediation of each mediator was subsequently calculated.

Findings: Red and Yellow areas of Boston were associated with an 11•1 (95% CI 5•5,22•4) and 11•4 (5•7,22•8) increased incident rate of shooting when compared to Green. In the pathway between Red designation and firearm incident rate, poverty and poor educational attainment mediated 20% of the interaction, share of rented housing mediated 8%, and Black share of the population 3%. In the pathway between Yellow designation and firearm incident rate, poverty and poor educational attainment mediated 16% of the association, and Black share of the population mediated 13%.

Interpretation: Redlining practices of the 1930s potentially contribute to increased rates of firearm violence through changes to neighborhood environments, namely through preclusion from homeownership, poverty, poor educational attainment, and concentration (i.e. segregation) of Black communities. These downstream mediating factors serve as points for policy interventions to address urban firearm violence.

Funding: Michael Poulson and Miriam Neufeld were supported by T32 Training Grants (HP10028, GM86308).

Keywords: Firearm violence; Health policy; Socioeconomic; Structural equation modeling; Structural racism.

Figure 1

Theoretical framework on which Structural Equation Model was built. Harmful HOLC designations (Yellow and Red) were compared to Green as the reference group in the direct pathway between HOLC classification (X) and the firearm incident rate (Y), the direct pathway between HOLC classification (X) and the mediator of interest (M), the direct pathway between the mediator of interest (M) and firearm incident rate (Y), and finally the indirect pathway from HOLC designation (X) to firearm incident rate (Y) through each mediator (M) of interest.

Figure 2

A) Crude shooting rates (per 1,000 people) in Boston between 2016-2019 by Census tract and B) vector representation of original 1930s HOLC redlining map of Boston.