Author: cherylcheung

Residential Micro-Segregation via Street Barriers in Lima, Peru

By Fernando Calderon Figueroa

Description of the Study

This study addresses the relationship between residential micro-segregation, in the form of built barriers to urban mobility, and social capital. Most of the scholarship on residential segregation posits the neighbourhood as its most relevant scale of analysis, while discussing built barriers as expressions of pre-existing social boundaries and as the result of higher-status groups’ attempts to seclude themselves from lower ones (Caldeira 2000; Garrido 2019; Massey and Denton 1993). A recent thread of studies has shown the importance of the street level for segregation patterns by bringing attention to the built environment (Grannis 1998; Grigoryeva and Ruef 2015; Logan, Graziul, and Frey 2018; Roberto 2018). Following this line of work, I draw on the notion of spatial micro-segregation to describe the patterns of urban fragmentation that result from resident-driven street enclosures within and across neighbourhoods.

I attempt to empirically test two theoretical propositions:

  • Residential micro-segregation is a socio-spatial process that occurs in the more recently developed residential areas of highly unequal cities that cuts across socioeconomic and ethnoracial boundaries.
    • Empirically, this proposition implies that micro-segregation must be pervasive throughout residential neighbourhoods and particularly concentrated among the most recently developed ones. There should be no correlation between the density of street barriers (e.g., gates, fences) and the socioeconomic or ethnoracial heterogeneity within and across neighbourhoods.
  • Residential micro-segregation negatively impacts the development of social capital and sentiments of community. Barriers to mobility express a form of social closure defined by location that interacts with the existing sociodemographic and ethnoracial composition of the neighbourhood.
    • Empirically, this proposition suggests that measures of social capital (e.g., interpersonal trust) should have decreased in the past few years in areas of the city with higher concentrations of street barriers.

To test these hypotheses, I use the case of Lima, Peru. I draw on the OpenStreetMap project (OSM) to identify the thousands of street-level barriers to mobility built in the city since the late 1990s. OSM is an open access platform, which allows the data to remain public beyond the scope of this study. While a fraction of street barriers has been reported, I am completing the data using georeferenced photographs posted on Mapillary and directly collecting images using an unmanned aerial vehicle (UAV or drone). The sociodemographic and ethnoracial composition comes from the block-level sociodemographic data published by the Peruvian National Institute on Statistics and Informatics (INEI) for the most recent census years (2007 and 2017). To assess social capital changes over time, I use an annual survey (N≈1,200 per year) on community issues conducted since 2010 called Lima Cómo Vamos.

This paper aims to expand our current knowledge about segregation patterns and their implications for social capital in highly unequal cities such as those in Latin America and throughout the Global South. I expect to complete a draft of the article by the end of 2022.

Preview of Spatial Analysis

Here is a preview of the street barrier data collected so far using OSM. The map shows the barriers, by category, in Villa El Salvador, a district in the south of Lima.


Caldeira, Teresa P. R. 2000. City of Walls: Crime, Segregation, and Citizenship in São Paulo. University of California Press.

Garrido, Marco. 2019. The Patchwork City: Class, Space, and Politics in Metro Manila. University of Chicago Press.

Grannis, Rick. 1998. “The Importance of Trivial Streets: Residential Streets and Residential Segregation.” American Journal of Sociology 103(6):1530–64.

Grigoryeva, Angelina, and Martin Ruef. 2015. “The Historical Demography of Racial Segregation.” American Sociological Review 80(4):814–42. doi: 10.1177/0003122415589170.

Logan, John R., Chris Graziul, and Nathan Frey. 2018. “Neighborhood Formation in St. Louis, 1930.” Environment and Planning B: Urban Analytics and City Science 45(6):1157–74. doi: 10.1177/2399808318801958.

Massey, Douglas S., and Nancy A. Denton. 1993. American Apartheid: Segregation and the Making of the Underclass. Cambridge: Harvard University Press.

Roberto, Elizabeth. 2018. “The Spatial Proximity and Connectivity Method for Measuring and Analyzing Residential Segregation.” Sociological Methodology 48(1):182–224. doi: 10.1177/0081175018796871.

New paper published! The Dilemmas of Spatializing Social Issues

Illustration by Fernando A. Calderón-Figueroa

Urban Genome Project Members Fernando A. Calderón-Figueroa, Daniel Silver, and Olimpia Bidian’s paper discussing Toronto’s Priority Area Program (2006–2013) has just been published in Socius: Sociological Research for a Dynamic World. Here’s Fernando’s summary:

Among the multiple ways to subdivide a city, neighbourhoods are probably the most familiar to our everyday experience. It is not surprising that neighbourhoods have been at the centre of revitalization efforts for almost a century. Yet, the early 2000s marked a transition towards systematic efforts to define neighbourhoods and their boundaries and identify the most disadvantaged among them. We call this process the spatialization of social issues, which was largely facilitated by the proliferation of Geographic Information Systems (GIS) technology in both academic and policy circles. More importantly, planning decisions that emerged from this trend affected neighbourhoods’ trajectories over time beyond policymakers’ original intentions.

Our paper explores the unwanted consequences of spatializing social issues in three steps. First, we examine whether designating entire neighbourhoods for social policy may affect their desirability as expressed in changes in rent and housing prices and in new building permits. Second, we assess the extent to which designated neighbourhoods may leave out areas “in need” that fall outside their boundaries while including better-off families within them. Third, we analyze evidence on whether this spatially-targeted policies may expand the stigma associated with certain places—e.g., a “dangerous” intersection or a “poor” housing complex—to all the designated neighbourhoods and the people within them. We draw on difference-in-difference models and income distribution analysis for first two parts, and on a qualitative assessment of newspaper articles and policy documents for the third one.

We make a twofold intervention in the existing literature on place-based policies. First, we bring together two social policy debates that share the common goal of attempting to improve the quality of life of those in areas of concentrated disadvantage. The “targeted” versus “universal” debate, heir to the 1970s welfare state scholarship, addresses the effectiveness and drawbacks of each of these approaches. The second is the “individual” versus “place” debate, in which researchers assess whether urban revitalization efforts should focus on individuals or entire places (e.g., “enterprise zones”). We bring together these traditions by treating each approach—targeted, universal, individual, and place—as dimensions in a two-by-two table. This intervention allows us to identify the potential negative externalities of neighbourhoods as policy targets (the targeted-place approach) while uncovering the potential of less-explored possibilities beyond spatial designations (the universal-place approach). Our second intervention is to bring to the fore a sociological conception of the neighbourhood that highlights its singularities as a scale of policy intervention. We suggest that neighbourhoods are interwoven in the urban landscape—thus, treating them as isolated entities poses significant challenges—and that their reputations matter for people’s self-conceptions and decision-making processes.

The study examines these ideas through the case of the Toronto Strong Neighbourhoods Strategy as it was implemented between 2006 and 2011. The program established 13 “priority areas for investment” and aimed to channel federal, provincial, and municipal resources into underserved communities to improve their social infrastructure. This was a response to the increasing poverty and crime rates in Toronto’s inner-suburban neighbourhoods. Previous research has found mixed evidence of the program’s effectiveness. However, we focus on assessing its unintended consequences, particularly regarding the lasting impact of the “priority neighbourhood” label as a shorthand for the target areas even after the program was relaunched in 2011. We find that, compared to otherwise similar and nearby places, those that received the “priority” designated had substantially lower growth in home prices, building permits, and rents.




Figure 2. Graphs (a) and (b) show trajectories comparing undesignated (red) and designated (light blue) DA paths on average monthly rent (left), average dwelling value (centre), and the cumulative sum of building permits (right) before (a) and after (b) matching. In graph (a), the markedly different trajectories respond to comparing the priority areas with the rest of the city. Graph (b) shows narrower trajectories albeit the growing gap between undesignated and designated areas across the three outcomes remains. Finally, graph (c) splits the priority areas between neighbourhoods designated by the CSP (green) and those included by the SNTF (light blue). The plots in graph (c) show that the gap between undesignated and designated DA paths grows wider over time for the CSP priority areas. Each outcome (column) has a different scale. 

The paper does not aim to entirely dismiss place-based policies but to expand how we think about them. Current location-based technology allows better ways to identify neighbourhoods and people’s needs for social infrastructure based on mobility and consumption patterns, street connectivity, among other measures, rather than relying on imposed official boundaries. Targeted policies may be combined with more universal approaches that reduce spatial inequalities while using resources efficiently. Our goal is to bring back sociological view of neighbourhoods as complex and interdependent foci of social life rather than isolated policy targets.

Listen to lead author Fernando A. Calderón-Figueroa discuss this paper by streaming the video below.

New Paper: “The Space of Ideas: Public Art Policies and the Concept of Urban Model Spaces”

an illustration of cloud gate (bean) in chicago

Noga Keidar and Dan Silver are  excited to announce the publication of their paper in The Journal of Urban Affairs. As a PhD candidate in the Department of Sociology at the University of Toronto Dr. Keidar was inspired to follow public art policies in order to examine the evolution of policy ideas and explain the mechanisms behind their mutations: “Our exploration started in 2016 as part of a research group of scholars from the U of T and OCAD U that worked to improve Toronto’s Percent for Art mechanism. We began collecting policy materials from cities comparable to Toronto to get ideas about how things could be done differently. We were surprised by the richness of policy materials cities produced, and more importantly by the great variance of values, goals and procedural arrangements that developed from this relatively basic policy tool. We wanted to systematically examine how the concept developed over time, across physical space and institutional settings, and to explain why cities used it differently. A key challenge was to develop a method and a theoretical framework to compare many cities. This challenge urged us to develop the Urban Model Space that could be applied in a textual analysis for any other popular policy model. 

Here is a short synopsis of the paper:

One of the central components of the theory of urban evolution concerns the circulation of urban ideas. Ideas about how to physically organize space, what to do there, and who should be there – forms, activities, and groups – carry from place to place what we term “formemes” in “Towards a Model of Urban Evolution.”

Our forthcoming article, “The Space of Ideas,” elaborates a novel approach to studying the role of urban ideas in urban evolution. Using a large corpus of public art policy documents from 1959-2020, we use computational text analysis to uncover the latent structure of the Anglosphere public art discourse and how it evolves along three key dimensions: temporality, scale, and position. We find six recurrent themes predominate in what we term the public art “Urban Model Space.” These themes include topics we describe under headings such as “pedestrianism,” “equitable access,” “creative industries,” “place-based identity,” “creative opportunities,” and “heritage.” Our analysis shows that the adoption of these themes is shaped by factors such as when a city initiates a public art program (temporality), the region or state in which it is located (scale), and its position in the global urban hierarchy or internal agency leading its public art initiatives (position). While the analysis offers important insight into the domain of public art, it also serves as a model for incorporating textual representations of ideas into urban evolutionary research.

To read the full article, click here.

Our study builds upon a dynamic and robust research tradition into Urban Policy Mobility. During the last two decades, this research stream has been documenting an extensive ‘flow’ of “urban models”, like Business Improvement Districts, Arts and Cultural policy, Climate Solutions and Insurgent Practices of slums and shack dwellers (McCann and Ward, 2010; Cociña et al., 2019; Wood, 2016). While these urban models are often described as ‘one-size-fits-all’ formulas shaped by homogenizing forces of globalization, they also generate replications and mutations that may be more ‘progressive’ or ‘conservative’, ‘market-led’ or ‘community-oriented’, depending on the interactions with a particular city (McCann, 2011; Jacobs, 2012). The attempt to assess the local formulation of a model is often tackled through a case study method that follows the local translation and compare it with few other translations. However, to fully understand policy replications and mutations, we must examine various translations of the ‘same’ model and locate them as part of the broader structure that explains their emergence. Our study proposes a complementary approach to the standard detailed case study – a textual analysis that delineates the Urban Model Space in which the implementation of the model in a specific location is situated alongside others.

To illustrate the approach, we use public art policy and in particular the Percent for Public Art ordinance – a common funding mechanism in the Anglosphere of setting aside a percentage of the city’s capital budget for public art. We sketch the space of the public art policy model using a corpus of public art policy documents from 26 cities with more than one million residents in the Anglosphere, including Australia, Canada, the United Kingdom, and the United States. These documents cover the period from when the ordinance was first applied in Philadelphia in 1959 (Carlin, 2004) until 2020. The corpus consists of four types of documents: public art plans, broader cultural plans with public art sections, guidelines, and open-ended research reports. These documents are used for various practical purposes, like creating a basis of common knowledge, standardizing technical procedures, promoting a policy change, or publicizing the city’s policy models over the world. After identifying the main discourses describing public art with Structural Topic Models (STM), we determine where, when, and why they were adopted with a series of regression analyses. Specifically, we ask: How have public art discourses changed over time? Which scale matters more for which topic? And which types of positions matter for the adoption of each discursive category?”

Public-Spiritedness in the Metropolis

What place is there for public spiritedness in the metropolis? Here, public spiritedness is broadly defined as a sense of obligation to others, which is presupposed by a sense of community. This definition considers the humanity of others, even if they are strangers. It suggests that there is a spirit, a personal philosophy, that is rooted in the desire to consider the welfare of not just the self, but of others too. Public spiritedness in this sense is most conducive to desirable outcomes in a society when it is practised by the masses. Otherwise, the incentive to care for others when others do not care for you diminishes. There is no pleasure in being a victim amidst a collective action problem: no one wants to be in an unfair position of supporting a “free-rider”. As such, public-spiritedness is a way of life that is practised by the self, but yields maximal benefit and becomes most compelling when it is practiced by a collective.

The anonymized nature of being in a city makes the practice of public-spiritedness more difficult than in a smaller community—like one typical of a rural area. In a city with millions of people, it becomes more difficult to consider the humanity of others due to the impossibility of meaningfully engaging with a sizeable fraction of a city’s residents. This lack of engagement not merely inhibits one’s ability to consider the humanity of the other when most of the others are unknown. It also inhibits one’s ability to gauge the level of public-spiritedness practiced by others in the city. As such, it may seem that the rational position is to act selfishly without regard for other community members.

Given the desirability of public-spiritedness, what place does it occupy in a city? Surely, there ought to be physical venues in which acts stemming from public-spiritedness can be displayed. Displays of this sort are prime examples of “signals” in the Toronto Urban Evolution Model: they transmit ideas about how to properly organize urban life. Signals can include formal material such as policy documents but they also include the everyday ways in which urbanities communicate to one another the models of urban life they value. Accordingly, some physical venues may signal the practice of selflessness to deter suspicions relating to collective action issues, but also emphasize the goodness of a city’s inhabitants. But the practice of public-spiritedness is also a private one that manifests in situations away from the public eye. To be conscientious of the humanity of the other requires an internalized understanding of how neighbours, no matter how near or how far, are people, too. They may be someone’s mother or someone’s brother. They have basic needs like access to food and water, but also personal needs like dignity and love.

This essay will focus on the porch as physical places for cultivating public- spiritedness and a key site for the evolution of “formemes.” It does not suggest the decline of the porch coincides with the loss of a sense of public-spiritedness, as Richard H. Thomas suggests in his “From Porch to Patio.” This essay is a celebration of the porch as an historically significant space for public gathering, both intentional and accidental.

Porches have evolved over millennia to reflect architectural waves and cultural contexts. Porches predate the bible, in which they may be referred to as “covered ways,” “porticoes” and “colonnades.” The porch, in the biblical context, more closely resembles the agoras (open place of assembly) observed in Greek documents like Plato’s Republic. By this, I mean the porch is a place at which individuals congregate intentionally, rather than on a whim as one might in the case of a neighbor’s porch in the context of a modern American suburb. In Acts 5:12 (Common English Bible), “The apostles performed many signs and wonders among the people. They would come together regularly at Solomon’s Porch.” This porch is not a small enclosure by a home’s entry way. This religious place of prayer and miracle is more fittingly built as a long pillared walkway running the entire eastern side of the Temple’s Outer Court in Jerusalem. As Solomon’s Porch, along with the rest of Herod’s temple, was destroyed by the Romans in A.D. 70, modern-day understanding of porch’s purpose and appearance largely relies on its observations in the Bible.

The porch has lived on as a symbol for congregation vital to the health of communities. TADAMUN Initiative declares “public libraries, community centers, public schools and places of worship […] [as] the “front porches” of civil society” in their declaration for the need of public spaces “accessible to all citizens, regardless of race, age, gender, income, or religion”. Here, the porch is a space not exclusive to any religious population: it is an open and public space to achieve the goods necessary for a community’s standards of a good life (e.g. access to education, social connection, freedom to worship).

Robert Putnam, when referring to social capital in “Bowling Alone,” also mentions the role of the porch in a healthy community. He observes “porch stoops” as places for “the community ‘mothers’ [to serve] as the neighborhood’s eyes and ears”. He admires the Rosteans, the inhabitants of Roseto, a modest village nestled in Eastern Pennsylvania, for their abundant social capital: “By day they congregated on front porches to watch the comings and goings, and by night they gravitated to local social clubs. In the 1960s the researchers began to suspect that social capital (though they didn’t use the term) was the key to Rosetans’ healthy hearts.” In this context, the porch is a necessary venue for companionship and support during the day. In his research on the decline of social capital, Putnam observes the rise of vocational communities amidst the decline of locational communities (like the Rosteans’). In writing, “perhaps we have simply transferred more of our friendships, more of our civic discussions, and more of our community ties from the front porch to the water cooler,” Putnam suggests the function of the porch has been transferred from home-based to work-based spaces.

Like Putnam, Richard H. Thomas identifies the necessity of deliberation among community members and likewise the importance of spaces to host such deliberation. In his “From Porch to Patio,” he laments the fall of the front-facing porch amidst the rise of the private, enclosed back patio. Whereas the sense of community that “often characterized the nineteenth-century village resulted from the forms of social interaction that the porch facilitated,” the “twentieth century man has achieved the sense of privacy in his patio [in exchange for] part of his public nature” (126-127). The back facing patio, irrespective of whether it is enclosed or not, is by nature private from the public eye. As such, its occupation by inhabitants however social or its decoration by landscaping however intricate, would not invite impromptu deliberations or even mere interactions from passersby. The back patio is engineered to deter the cultivation of public- spiritedness, it is a refuge from the public in attempt to maintain privacy. The porch, by contrast, is an accidental venue for inviting nods of approval from passengers of carriages (121), impromptu deliberations by neighbours (compared to pre-planned neighbourhood coffees and bridge parties) (122), and quick greetings (122). These are all social interactions necessary in maintaining public-spiritedness. A love of the neighbor (referred to as ‘agape’ in the Bible), or the mere reminder of the humanity of the other requires the lived experience of social interaction. The porch has survived throughout millennia as a place for such interaction, and by extension: as the physical venue for cultivating public-spiritedness.

Encouragingly, Urban Genome Project member Khalil Martin’s research finds that the number of porches has dramatically increased in the past twenty five years. This disputes Richard H. Thomas’s theory of the porch’s decline amidst growing interest in back patios. Martin has found, using data from the U.S. Survey of Construction, that the proportion of American single-family homes that include a porch has increased from around 50% in 2000 to 64% in 2020. Furthermore, owner-built and contractor-built homes were consistently more likely to include a porch than homes built for sale or rent. This seems to indicate that people generally choose to have a porch when they can. 

Martin’s research finds that the porch continues to be recognized in North America to be an important social infrastructure and has gained status as “an icon for community and civic mindedness, through the spontaneous and liminal interactions it affords.” 

The American front porch has been used for a space for social rituals and ceremonies, such as summer tea rituals, courtship rituals, and seasonal events. Previously, American front porch has been used as a stage for performance and self-presentation, such as the various “porch campaigns” in early American politics, “porch concerts” (which also popularized during the pandemic), and even for social movements–for example when MLK preached on front porches. To add, the American front porch has also been used as a cultural signifier. Consider the adoption of Neo-classical porch styles by many statesmen, the mounting of national flags of porch posts, and other various style trends.


His research hopes to show how people have adopted, and adapted, threshold forms to meet their contexts and create collective identity. A further step is to also explore how the diversity and dynamism of threshold form features and uses relate to the notion of community thriving. Khalil frames his work as a means to “understand the opportunities for spatial agency and participation, in the urban context”

As a side note, Martin notes there may have been a decline in porch adoption between 1945 and 1995, but that data his research focused on ranged between 2000 and 2020.

Although the strength or spread of public spiritedness is difficult to measure, it should be encouraged on the basis of cultivating moral respect. I argue that greater consideration paid to the humanity of the other will bolster a sense of obligation to others, and consequently reduce partisanship and alienation common of large heterogeneous cities. Further thought should be devoted to porch-like spaces in public, vocational, and private spaces in the interest of supporting a good life for members of locational and vocational communities alike.

Upcoming Talk: Bernie Koch on The Evolutionary Dynamics of Cultural Change (As Told Through the Birth and Brutal, Blackened Death of Metal Music).

The Urban Genome Project at the School of Cities is hosting a talk next week by Bernie Koch on The Evolutionary Dynamics of Cultural Change (As Told Through the Birth and Brutal, Blackened Death of Metal Music).

This talk will be of special interest to those in the sociology of culture and computational social science, though it also has much broader import for general social theory and beyond . The talk will be on Thursday, February 3, 4:00 PM EST.

Please register by clicking here or by visiting this link:

We are looking forward to seeing you there!


How does culture change? We unify disconnected explanations of change that focus either on individuals or on public culture under a theory of cultural evolution. By shifting our analytical lens from actors to public cultural ideas and objects, our theory can explain change in cultural forms over large and long frames of analysis using formal evolutionary mechanisms. Complementing this theory, the paper introduces a suite of novel methods to explain change in the historical trajectories of populations of cultural ideas/objects (e.g., music groups, hashtags, laws, technologies, and organizations) through diversification rates. We deploy our theory and methods to study the history of metal music over more than three decades, using a complete dataset of all bands active between 1968 and 2000. Over the course of its history, we find strong evidence that the genre has been fundamentally shaped by competition between ideas for the cognitive resources actors can invest in learning about and reproducing this cultural form over time.

Speaker Bio

Bernard Koch is a PhD candidate in the sociology department at UCLA. Inspired by pre-graduate work in evolutionary biology and bioinformatics, his research now uses computational approaches to examine cultural dynamics in fields as diverse as science and music. In his work on culture, he seeks to wed theories of cultural evolution and cognition with formal models of population change from biology. Other projects elucidate how the culture and organization of scientific fields (e.g., machine learning, IQ psychology) create ethical and epistemic challenges. Lastly, he has broad interests in Bayesian modeling, machine learning, networks, and causal inference. His research has been published at NeurIPS, WWW, Sociological Methodology, and Science, among other venues.