Residential and Experienced Urban Segregation

Introduction

Economic segregation is “the geographic manifestation of income inequality”. Consequently, the recent growth in income inequality in many economies reflects itself in growing socioeconomic segregation in cities. For instance, neighborhood segregation in NYC and Philadelphia grew by 40% in the 1970-2010 period (Mijs & Roe 2021). Segregation also grew in other US and European cities and in Latin America. This increasing socioeconomic segregation has a host of alarming negative consequences, such as creating an unequal access to local public goods (e.g. good schools and parks). This in turn undermines social mobility and societal cohesion. Thus, it is important to know what governments can do to stop the trend of increasing socioeconomic segregation in large cities.

Against this backdrop, this PhD project studies how specific urban planning policies affect the degree of socioeconomic segregation in cities. This is interesting from a policymaking perspective since urban planning (e.g. land use regulation or public transit) are central to the location choice of rich and poor households within cities. For local governments, urban planning also often the key instrument to address socioeconomic segregation, as other instruments are the competencies of state or federal governments. The PhD project is also interesting from an academic perspective, as new developments in urban planning, such as the paradigm of urban densification,  raise new questions about segregation in urban areas. Furthermore, new fine-grained big data from web-scraping or cell phones’ GPS location enable this project to study the effects of urban planning policies on segregation and residential location choice in more detail.

The Project

This PhD project seeks to understand the effect of changes in land use regulation and public transit provision on residential and experienced socioeconomic segregation in Zurich in Switzerland and Bogotá in Colombia. The project uses geo-spatial observational data and state-of-the-art methods of causal inference. Specifically, this PhD project consist of two blocks:

Densification & Residential Segregation in Zurich

• Research question: What is the effect of changes in land use regulation that allow for more densification on rent prices and residential income segregation in the Canton of Zurich? Do densification policies lead to the replacement of old low-rent housing stock with newer, high-end housing and thus drive up rents leading to displacement of poorer households?
• Methods: The project analyses data on land use plans, construction activity, rents and administrative data on household income, education and movement decisions. The investigators use staggered difference-in-difference regression to causally identify the impact of changes in land use regulation on rents and socioeconomic household sorting. Some project parts also zoom in on certain train stations using case studies.
• Preliminary results: Current results show that on average changes in land use do not lead to faster rent increases in treated areas compared to other non-treated areas. Yet, this strongly depends on initial neighborhood characteristics: if a neighborhood is initially relatively poor, but centrally located and well connected, then more construction happens and rents increase. This shows that the effect of the new planning paradigm of densifying cities can vary strongly, and that poorer neighborhoods need additional measures to avoid local rent increases.

Experienced Segregation & Public Transit in Bogotá

• Research question: The project studies experienced segregation, defined as the segregation by income and gender in public and semi-public paces, such as restaurants, parks or bus stops (see e.g. Moro, Calacci, Dong & Pentland 2021 for more information). Which individuals live the most segregated lives? Does good access to public transit decrease experienced segregation for low and middle-income individuals?
• Methods: The project uses GPS data from cell phones and Google points of interest data to investigate how likely an individual is to co-locate with individuals from different socioeconomic groups or a different gender in public and semi-public spaces. After identifying broad general patterns of experienced segregation of Bogotá’s inhabitants, the project studies whether comparable individuals living in areas with good access to public transit live less segregated everyday lives.

Neave O’Clery (UCL CASA)
Samuel Heroy (University of Oxford)