Research Highlights Podcast
September 11, 2025
Reviewing residential segregation
Trevon Logan and John Parman discuss the meaning of segregation and how it has shaped US history.
Source: Grandbrothers
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Despite decades of civil rights legislation, many Black and White Americans, as well as other minorities, continue to live in racially homogeneous neighborhoods, with significant implications for access to quality schools, jobs, healthcare, and economic opportunities.
In a paper in the Journal of Economic Literature, authors and examine the complexities of measuring residential segregation, what causes segregation to persist, and why it matters so much for economic outcomes. Their work challenges conventional narratives about US segregation and offers a framework for understanding how residential patterns continue to shape American inequality.
Logan and Parman recently spoke with Tyler Smith about the patterns of segregation they uncovered, and what the key drivers might be.
The edited highlights of that conversation are below, and the full interview can be heard using the podcast player.
Tyler Smith: In your study, you performed a review of segregation research by economists, as well as some work by sociologists and demographers. How does this literature define residential segregation?
Trevon Logan: One of the things that we faced here was that there basically are two ways that people understand segregation. There’s a popular sense and then there’s the way that academics think about segregation, which is much more of a technical measurement issue. When people say segregation in popular discussions, they’re often thinking about neighborhoods or areas of a city, for example, that are disproportionately belonging to members of one racial group. But I think when people talk about segregation it is an amorphous blend between segregation as we're describing it, i.e., residential segregation, and school segregation or occupational segregation. When you get into the technical measurement of segregation, it's really difficult because the first thing is when I talk about segregation and how those people live “over there,” I have to first define what “there” is. Am I talking about “there” as a quadrant of the city? Am I thinking of “there” as a Metropolitan Statistical Area? What is the scale in which I'm thinking about segregation? And how do I actually quantify or measure segregation?
Smith: What are the special challenges that come with trying to measure segregation?
John Parman: I think the most fundamental challenge is that once you quantify something, you're focusing on one particular dimension of it and you're losing a lot of other information. It really depends on what particular aspect of segregation you want to capture. We can do a good job of measuring that. But in doing so we're kind of tossing out all the other different relevant characteristics. A really simple example of this is thinking about how fine of a geographic unit we want to use for a neighborhood. You have to define that if you want to say this neighborhood is disproportionately White or this neighborhood is disproportionately Hispanic. You have to have that boundary in mind. But why does that matter? Does it matter because of which school your children would go to? Does it matter for access to healthcare? Does it matter for access to grocery stores? Does it matter for interactions with people? I might want to think down to maybe the block level if it's about which neighbors you bump into each day. But if I'm thinking about what sort of political representation you have, then I'm using a much larger area. That's really the challenge. We've got really rich data on where people live and where people work. We even have data now on where cell phones are being used, so we can track people throughout the day. But we have to make this really basic decision as researchers of what's the right unit to look at. And that's kind of a more conceptual question rather than just computing a number.
Smith: What major patterns have researchers in this field uncovered?
Parman: What stands out most to me in this literature is that to tell the story of what our cities and rural areas look like, you really have to tell at least a couple centuries of history. If you think about the really long-run nature of this, certainly for Black–White segregation, the initial distribution of the black population was dictated by slavery and cash crops. You still see echoes of that in the more rural areas of the South. If you look at the composition of those counties, it still maps back to those original plantation economies. So we start there, and then as cities grow, as people move from the farm to the city, this is where we start to see the rise of urban segregation throughout the 20th century, which peaked around the 1970s. And then we've seen it drop off a bit after that. One fascinating thing we've seen in some of our own research is that so much of the focus on segregation is about urban areas, about cities or city centers versus suburbs. If you measure segregation in rural areas, though, you see similar patterns. You see it rising over the first half of the 20th century. And so we really need to broaden how we think about what segregation means when we think about those patterns.
Smith: You organize the possible causes of segregation in the United States into three broad categories. You call them a port of entry cause, a collective action cause, and a decentralized racism cause. First, what are we talking about when we call something a port of entry cause in this literature?
Logan: I think of the port of entry as the “nation of immigrants” story of immigration. Taking out the Native American population, everyone else came to the United States. I think the first thing I would want to stress is we're talking immediately about people belonging to groups. Typically if we're telling the story about immigrants, or thinking about the Irish, or thinking about Polish immigrants, or thinking about Russian Jewish immigrants, for example, coming to the United States, the way they first arrived is through a port of entry. The port of entry allows the development of these ethnic enclaves. Developing these urban communities solves a lot of problems for them. There are communication issues. There's the development of businesses. There's also just the need to satisfy individual taste and preferences for things like food and entertainment that ethnic enclaves serve. And then as one develops and integrates into the economy, the need for that neighborhood can decline. And then we see a large number of African Americans, in particular, in cities move in. And so that's the port of entry sort of story of segregation, which is that you create these ethnic enclaves. They themselves are segregated by ethnicity. And subsequently, when they become racially distinct, then you have the racial segregation that we measure.
Smith: What are the collective action forces of segregation?
Parman: I think these are forces that you see pop up in the news and the popular press quite a bit. There's been this huge interest in things like redlining in the past or racially restrictive covenants on deeds. These are areas where essentially you're using the political institutions, the legal framework, to enforce these segregated areas. It's not simply people making their own individual decisions of where to live. People's decisions are restricted by things like these laws. Moreover, there's a group that's pushing for those laws to be in place. And so that's effectively the collective action, though there's a lot of ambiguity there when you actually try to measure how these things take place. I'll give a very personal example. I teach a lot about these racially restrictive covenants in my class. Shelly v. Kramer, which was decided in 1948, is the Supreme Court case that says these are unenforceable; they're unconstitutional. My house has a racially restrictive covenant in its deed four years later in 1952. And so there's this really difficult thing of exactly which laws and which institutions are binding and who really is creating those. The people that owned my house still put those into place and they still had some influence on the development of my neighborhood. So it is a straightforward concept in some ways to say what these collective action mechanisms are, but exactly how they play out is really complex.
What stands out most to me in this literature is that to tell the story of what our cities and rural areas look like, you really have to tell at least a couple centuries of history.
John Parman
Smith: Finally, you all highlight what you call decentralized racism. What is that about?
Logan: To pick up on something that John is talking about, a lot of people have this presumption that the covenants just say you can't sell the home to Black people, but if you actually go into these covenants, they don't just say no Black people. Some are so absolutely specific. They will say no southern Italians can live here. They're very restrictive about a number of different groups. And you'll see these restrictions in places where these people were a very small part of the population, like in Iowa. And so what historians have now figured out is that it was realtors who were using these deeds as examples when communities were first being formed; it was essentially a template. How does that link to decentralized racism? These are individual deeds that are then enacted by a lot of people, and so there's not a central authority saying you have to have this sort of practice, but this is the way in which people are actually individually moving and making these sort of collective decisions. If you think about where people are actually sorting amongst themselves, this is where the role of individual preferences combines with collective action to form these norms that persist over time. If you think about collective action, you think about these sort of institutional rules that take place. But decentralized racism is thinking about what are the underlying preferences that give rise to these sustained actual conventions that you see. We typically see it in the reaction to something that is a desegregation process. We see it in efforts to desegregate schools, for example.
Decentralized racism is a political economy issue. It’s about who you do or don't want to share public goods with, such as schools, infrastructure, and policing. If you form a municipality that is separate from, say, the central city, you now have actually restricted the group of people that you're making decisions with. And so that's a way in which decentralized racism can lead to the collective action that we see, which can then take the form of zoning laws, for instance. In other words, if you get a lot of people who have similar preferences together, that will be the baseline in which all of these things are actually operating. In the end, you still have to have people with some preference for homogeneous communities. It's important to understand that everyone in any group that we're thinking about has weak preferences, at a minimum, for being around people of their own group. But some groups have stronger preferences than others.
Smith: What are the biggest takeaways from this literature on the consequences of residential segregation?
Parman: I think what's received a lot of attention historically and is still really relevant today is schooling resources. That’s one of the biggest things that comes to mind. And this is because schooling is based on where you live and how we do our school funding. And so if you have high property values and you're funding your schools through those local property taxes, that creates these huge differentials in school quality across really short distances. That's where I think you see this very direct, very clear impact of residential segregation. I'd say that always stands out to me as one of the biggest things and the clearest indication of why these local boundaries matter and how the way that we define public goods and pay for them matter in relation to those boundaries.
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“Racial Residential Segregation in the United States” appears in the September 2025 issue of the Journal of Economic Literature. Music in the audio is by .