A 'SOCIOPHYSONOMIC'
MODEL OF GENTRIFICATION
BIRMINGHAM, ALABAMA | SPRING 2021
Various socioeconomic factors have traditionally been considered the primary causes of gentrification. This Masters thesis instead examines the historical role of the built environment in contemporary patterns of neighborhood level demographic change. The focus of this study is primarily on the compounding predictive ability that numerous gentrification susceptibility factors can have when layered atop a single neighborhood rather than just on the importance of any single causal mechanism alone. The study first proposes a hybrid model of gentrification under which such demographic shifts are primarily caused by the interplay between racist housing policies and disruptive redevelopment practices within the built environment. It then tests the saliency of this proposed model in a case study of Birmingham, Alabama. Most models of gentrification have been tested primarily in the larger urban areas of the United States. This study’s model is applied to Birmingham, Alabama in order to test its internal validity and its applicability to mid-size American cities. The methodology for the testing of the model is as follows:
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The basic framework of this study’s sociophysonomic model holds that gentrification is produced at the intersection of certain social, physical, and economic systems. In order to test this model, the social, physical, and economic systems in question were operationalized into variables that could be measured. This study proposes that Birmingham’s current and future gentrification is not merely a byproduct of contemporary free market economics, but rather the outgrowth of racist housing policy and disruptive redevelopment from the city’s past catalyzed by broad reinvestment. Racist housing policy is the social variable and is operationalized as racial residential zoning and redlining. Disruptive redevelopment is the physical variable and is operationalized as urban renewal areas and neighborhoods. Broad reinvestment is the economic catalyst variable and is operationalized as the number of proposed and recently completed multimillion-dollar developments in a neighborhood.
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To test the prognostic ability of the model, its operationalized variables were mapped to predict which areas in Birmingham were most likely to gentrify based on historic sociophysonomic determinants. Working under the study’s claim that geographically layered sociophysonomic systems compound the ability and likelihood of a neighborhood to gentrify, the model predicts that the neighborhoods where racial zoning, redlining, urban renewal areas, highway construction, and broad reinvestment overlap have the highest likelihood of gentrifying. Therefore, the areas in Birmingham where all of these factors historically overlap are predicted to be the sites of 21st century gentrification.
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In order to test the model’s predictions against the reality in Birmingham, a multi-prong analysis of which neighborhoods actually gentrified from 2010 to 2019 is employed. Census tracts are used to substitute for neighborhood level analysis, and only tracts within the city limits of Birmingham are considered in order to maintain the study’s focus on gentrification in urban neighborhoods. Gentrification as a variable is operationalized as increasing median household income, the percentage of white residents in minority neighborhoods increasing, and increasing median gross rent. Each of these variables is gradated to show neighborhood level demographic change as heavily decreasing, moderately decreasing, relatively stable, moderately increasing, or heavily increasing. Neighborhoods increasing in at least two of the three factors with at least one of those increases being heavy qualify as having actually gentrified during the 2010s. The predicted gentrification sites are then compared to the actual gentrification sites to determine the accuracy of the study’s sociophysonomic gentrification model.
Figure 1: Areas of Birmingham Zoned for Black Residents under the 1926 Zoning Code
Figure 2: Areas of Birmingham Redlined under the 1938 HOLC Residential Security Map
Figure 3: Urban Renewal Areas in Birmingham
Figure 4: Interstates and Major Highways in Birmingham (interstate freeways = thicker lines / major highways = thinner lines)
Figure 5: Spatial Intersections of Racist Housing Policies & Disruptive Redevelopments in Birmingham
Figure 6: Predicted Foci of 21st Century Gentrification based on Factor Overlay
Figure 7: Actual Gentrification based on Increase in Median Household Income, 2010 - 2019
Figure 8: Actual Gentrification based on Increase in Caucasian Share of Population, 2010 - 2019
Figure 9: Actual Gentrification based on Increase in Median Gross Rent, 2010 - 2019
After conducting a test of this study’s sociophysonomic model of gentrification in a case study of the phenomenon in Birmingham, Alabama, the predicted foci of gentrification aligned perfectly with the neighborhoods that actually gentrified on multiple metrics from 2010-2019. This supports the integrity of the study’s sociophysonomic model that is based on the intersection of racist housing policies (social systems), disruptive redevelopment (physical systems), and a catalyst of broad reinvestment (economic systems) as a credible operative theory of gentrification. This makes my model highly useful as a tool in predicting gentrification not only in Birmingham, but in other cities throughout the nation that have suffered from similar trends of racial zoning, redlining, urban renewal, and disruptive highway development and are also undergoing renewed investment in the areas affected by those trends. Therefore, gentrification can be forecast and proactively addressed instead of the ineffective reactionary measures that have been taken in most cities.
