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Segregation Index

The segregation index is a number that shows how separated racial or ethnic groups are across neighborhoods. In Ethnic Studies, it helps you measure housing inequality and the effects of segregation.

Last updated July 2026•Fiveable Content Team

What is the Segregation Index?

The segregation index is a numerical way to measure how separated racial or ethnic groups are in housing patterns. In Ethnic Studies, it is used to show whether different groups live in mixed neighborhoods or in areas that are divided by race or ethnicity.

The basic idea is simple: if two groups are spread across the same neighborhoods in similar proportions, segregation is lower. If one group is concentrated in a few areas while another group is concentrated elsewhere, the index rises. That makes it a useful tool for turning a big social pattern into something you can compare across cities, counties, or census tracts.

A segregation index is not one single formula. Common measures include the Dissimilarity Index and the Isolation Index. The Dissimilarity Index often asks how evenly two groups are distributed, while the Isolation Index looks at how likely members of one group are to live mostly among themselves. Different indices can tell slightly different stories, so the number you see depends on what is being measured.

In Ethnic Studies, the index matters because segregation is usually not random. It connects to policies and practices like redlining, restrictive housing access, and unequal lending. When neighborhoods are separated, the effects often show up in schools, transportation, healthcare access, and job opportunities.

That is why this term is more than a housing statistic. It is a way to trace how race, power, and space interact. If a city has a high segregation index, you are looking at a pattern that usually reflects social history, not just personal preference.

Why the Segregation Index matters in Ethnic Studies

The segregation index gives you a way to measure structural inequality instead of talking about it only in general terms. In Ethnic Studies, that matters because housing patterns shape who gets access to better-resourced schools, safe streets, stable home values, and nearby jobs.

It also helps you connect historical policy to present-day outcomes. Redlining and other discriminatory housing practices did not just separate neighborhoods once and leave them there. They helped build long-lasting patterns that continue to affect wealth, opportunity, and community resources.

This term is useful when you are reading about urban history, civil rights, or modern housing debates. If a passage or case study mentions segregation, the index gives you a way to ask, "How divided is the area, and what is driving that division?" That is the move Ethnic Studies often wants you to make: link a visible pattern to the deeper system behind it.

Keep studying Ethnic Studies Unit 11

How the Segregation Index connects across the course

Redlining

Redlining is one of the clearest reasons segregation indexes stay high in many U.S. cities. When banks and insurers refused services in neighborhoods tied to Black and immigrant residents, they limited where families could buy homes and build wealth. The segregation index helps show the long-term neighborhood pattern that grew out of those decisions.

Housing equity

Housing equity is the goal of fair access to safe, stable, and affordable housing across racial and ethnic groups. The segregation index shows where that goal is not being met. A city can have formal legal equality and still have a high index if neighborhoods remain separated by race and resources.

Income Segregation

Income segregation and racial or ethnic segregation often overlap, but they are not identical. Income segregation focuses on how households are separated by class or earnings, while the segregation index in Ethnic Studies usually tracks race or ethnicity. Comparing the two can show whether wealth, race, or both are shaping neighborhood patterns.

Gentrification Displacement

Gentrification displacement can change segregation patterns by pushing longtime residents out of neighborhoods they have lived in for years. That can lower segregation in one place while increasing it somewhere else. The segregation index helps you see whether neighborhood change is creating integration or just relocating inequality.

Is the Segregation Index on the Ethnic Studies exam?

A quiz question or short-response prompt may give you a map, table, or city housing pattern and ask you to identify segregation by reading the distribution of groups across neighborhoods. You would use the term to explain that a high segregation index means groups are unevenly separated, not just that they live in different areas.

In a passage analysis or discussion, you might connect the index to redlining, unequal lending, or school access. If a case study describes one group clustered in one part of a city and another group spread elsewhere, you should name that pattern and explain what the index would reveal. For an essay, the strongest move is usually to pair the number with a cause and an effect, such as housing discrimination leading to neighborhood separation and then to unequal resources.

The Segregation Index vs Income Segregation

Segregation Index and Income Segregation are related but not the same. Income segregation measures separation by class or household income, while segregation index usually refers to racial or ethnic separation in housing patterns. A city can be highly income-segregated, highly racially segregated, or both, so the context of the question matters.

Key things to remember about the Segregation Index

  • The segregation index is a number that measures how separated racial or ethnic groups are across neighborhoods.

  • A higher index means more separation, while a lower index means more mixing or integration.

  • In Ethnic Studies, the term usually connects to housing discrimination, redlining, and unequal access to resources.

  • Different segregation measures can highlight different patterns, so always check whether the text uses the Dissimilarity Index, Isolation Index, or another version.

  • The term is most useful when you want to connect a neighborhood pattern to larger systems of race, power, and policy.

Frequently asked questions about the Segregation Index

What is Segregation Index in Ethnic Studies?

The segregation index is a measure of how separated racial or ethnic groups are in housing and neighborhood patterns. In Ethnic Studies, it is used to show how segregation reflects discrimination, policy history, and unequal access to resources.

Is the Segregation Index the same as redlining?

No. Redlining is a discriminatory practice that denied services and loans to certain neighborhoods, while the segregation index is a measurement tool. Redlining can contribute to a high segregation index because it helps create and maintain separated neighborhoods.

What does a high segregation index mean?

A high segregation index means racial or ethnic groups are spread very unevenly across neighborhoods. In practice, that often points to housing discrimination, historic policy choices, or economic barriers that keep communities separated.

How do you use Segregation Index in a class answer?

Use it to describe a neighborhood pattern and then explain what caused it. For example, if a city map shows one group concentrated in one area, you can say the segregation index would be high and connect that pattern to redlining, housing discrimination, or unequal lending.