Neighborhood Racial/Ethnic Segregation



Why do we measure racial/ethnic diversity and neighborhood racial/ethnic segregation?

The geographic distribution of racial/ethnic groups across a congressional district plays a key role in understanding the health disparities within that district. 

Diversity. Since health outcomes can differ among people of different racial and ethnic groups, understanding the diversity of a congressional district can help explain patterns of health and needed interventions.  

Segregation. Residential segregation by race/ethnicity is associated with a range of adverse impacts on health – from cardiovascular risk factors and elevated rates of infectious diseases to premature mortality.(1,2) Racial/ethnic minorities in segregated communities are also more likely to have limited employment opportunities and lower incomes and to face shortages of safe and affordable housing – all key drivers of health.(2) In many communities, long-standing practices in the 1900s by banks, the real estate industry, and the judicial system, have contributed to patterns of residential segregation that endure to this day.(3,4)

How do we measure racial/ethnic diversity and neighborhood racial/ethnic segregation? 

Diversity. Racial/ethnic diversity (also known in other publications as the Entropy Score) represents the mix of racial/ethnic groups in a geographic area (census tract or congressional district), represented on a scale of 0 to 100.(5) A value of 0 indicates that all residents of the area belong to a single racial/ethnic category; a value of 100 indicates that all pre-specified racial/ethnic groups comprise an equal proportion of the population. This measure does not take the geographic distribution of racial/ethnic groups into account.

Segregation. Neighborhood racial/ethnic segregation (also known as the Entropy Index or Theil’s H) measures the extent to which a congressional district’s racial/ethnic groups are evenly represented across its census tracts. Like racial/ethnic diversity, neighborhood racial/ethnic segregation is represented on a scale from 0 to 100, but, for this measure, lower values indicate less segregation. A value of 0 indicates no segregation – all census tracts are fully representative of the congressional district’s overall racial/ethnic diversity. A value of 100 indicates absolute segregation – no census tracts have more than one racial/ethnic group residing in them.  

We measure both diversity and segregation because they are not the same. For example, a particular congressional district could be quite diverse, populated by many racial/ethnic groups, but members of these groups could be segregated into different neighborhoods. Alternatively, a city can also have low diversity, but be without significant residential segregation. Both metrics are useful in understanding these concepts.

Check out our blog post on our cities site, explaining these metrics for more information!



Unlike other measures of segregation, which often analyze the proportion of only two racial/ethnic groups in a geographic area, the neighborhood racial/ethnic segregation metric can account for the presence of multiple racial/ethnic groups.(5) 

Neighborhood racial/ethnic segregation measures the “evenness” of the distribution of racial/ethnic groups within an area. This is a validated and frequently used measure of segregation in academic literature.(6){Massey, 1988 #806;Massey, 1988 #806} 

Racial/ethnic diversity does not identify which racial/ethnic groups are the minority or majority. 

Neighborhood racial/ethnic segregation does not specify which racial/ethnic groups are segregated. Research suggests that Black-white segregation harms the health of Black populations, but effects are less consistent for other racial/ethnic groups.(7)

There are no “absolutely” good or bad values of diversity or segregation: The local context of the place must be considered when interpreting these estimates. 


We use three values to help understand a city’s racial/ethnic distribution: 

  1. a number describing racial/ethnic diversity at the congressional district level.

  2. a number describing racial/ethnic diversity at the censustract level.

  3. a number describing a congressional district’s overall racial/ethnic segregation.

This metric was calculated by aggregating estimates from smaller geographies to the congressional district level. For more information, please refer to the Congressional District Health Dashboard Technical Document or Iceland (2004).(5)

Data Source

Estimates for these metrics are from American Community Survey five-year estimate data using the DP05 table. 

NOTE: We categorize race/ethnicity into the following five categories: Asian (Asian and Pacific Islander); Black/African American; Other (American Indian and Alaska Native, two or more races, and some other race); Hispanic; and non-Hispanic white. Please see the technical document for more details. 

Years of Collection

Calculated by the Dashboard Team using data from 2021, 5 year estimate


  1. Collins CA, Williams DR. Segregation and Mortality: The Deadly Effects of Racism? Sociological Forum. 1999;14(3):495-523.

  2. Kramer MR, Hogue CR. Is segregation bad for your health? Epidemiol Rev. 2009;31:178-194.

  3. Massey DS, Denton NA. American apartheid: Segregation and the making of the underclass. Harvard University Press; 1993.

  4. Williams DR, Collins C. Racial residential segregation: a fundamental cause of racial disparities in health. Public health reports (Washington, DC : 1974). 2001;116(5):404-416.

  5. Iceland J. The multigroup entropy index (also known as Theil's H or the information theory index). US Census Bureau Retrieved July. 2004:1-10.

  6. Massey DS, Denton NA. The Dimensions of Residential Segregation. Social Forces. 1988;67(2):281-315.

  7. Kershaw KN, Albrecht SS, Carnethon MR. Racial and ethnic residential segregation, the neighborhood socioeconomic environment, and obesity among Blacks and Mexican Americans. Am J Epidemiol. 2013;177(4):299-309.

Last updated: February 20, 2024