Cleveland, Ohio. From the Tiger Mapping Service.

Cutler/Glaeser/Vigdor Segregation Data:
User's Guide

How Segregation Is Measured
Area Definitions
Sample Selection Criteria
Supplementary Variable Definitions
Citing This Work
References

How Segregation Is Measured

Segregation is the physical separation of members of one racial, ethnic, social, or economic group from members of another group. This dataset measures the segregation of blacks from non-blacks.

No single summary measure can fully characterize segregation, but several indices attempt to capture important aspects. All segregation indices require a city or similar area to be divided up into smaller geographic subunits. The racial composition of these subunits is then used to derive the various indices. Complete definitions of the indices presented here can be found in Cutler, Glaeser, and Vigdor (1999). For additional discussion of segregation indices, see Massey and Denton (1988).

Dissimilarity

The Index of Dissimilarity, proposed by Duncan and Duncan (1955) , measures the extent to which blacks and non-blacks inhabit different areas of a city. It ranges between zero and one, and can be interpreted as the fraction of blacks that would have to switch areas to achieve an even racial distribution citywide. Zero indicates perfect integration; one indicates perfect segregation -- i.e. blacks and non-blacks inhabit completely different areas. A value above 0.6 is generally considered high.

Isolation

Even if blacks are concentrated in certain parts of a city, they may have extensive contact with whites within those areas. The Index of Isolation, calculated with slightly different formulas by Bell (1954) and White (1986), measures the extent of black contact with non-blacks. This index also varies between zero and one, with higher values indicating greater black exposure to other blacks. Values above 0.3 are considered high.

Clustering

The Index of Clustering, defined by White (1983) measures the extent that black neighborhoods abut one another. In this respect, it overcomes shortcomings of the other indices, since they fail to account for the racial composition of neighborhoods surrounding any one area. Unfortunately, this index requires data on area latitude and longitude that we only have for 1990. The index varies (approximately) between zero and one, with a value of one indicating that all blacks (or non-blacks) live in one large cluster of neighborhoods.

Concentration

The Index of Concentration measures the extent to which blacks inhabit the physically smallest geographic subunits of a city. It ranges from -1 to 1, with extreme values indicating that blacks inhabit the largest or smallest areas, and a value of zero indicating a relatively even spread of blacks across areas. Calculating this index requires data on unit area which we only have for 1990.

Centralization

The Index of Centralization measures the tendency for a black population to be distributed close to a city's central business district. This index also ranges from -1 to 1, with higher values indicating greater centralization, and a value of zero indicating an even spread. Latitude and longitude data are necessary to calculate this index, thus we only present values for 1990.

Back to Table of Contents

Back to Segregation Data Home Page

Area Definitions

From 1890 to 1940, the Census published reports for city wards. Wards are political units which vary widely in population size and area across cities, for this reason they are not the ideal city subunits for cross-city comparisons. Beginning in 1940, the Census published tract reports. Census tracts are geographically compact areas, usually delimited by major streets, city boundaries, or natural features, and containing approximately 4,000 persons. Tracts are designed to be comparable units across cities and over time. Our segregation indices use wards from 1890 to 1940, and tracts from 1940 to 1990.

Ward-based indices tend to fall below tract-based indices simply because wards are larger areas. To correct for this discrepancy, we suggest using a correction factor of 0.152 for the Dissimilarity Index and 0.157 for the Isolation Index. These factors are simply the mean differences between ward and tract indices for the 47 cities that report both in 1940. Note that these correction factors have not been added to the data presented here.

Through 1950, segregation is defined at the city level. After World War II, rapid suburbanization led to the creation of Metropolitan Statistical Areas (MSAs), groups of counties surrounding a central city. Beginning in 1960, our indices use MSAs rather than cities. For further discussion, see Cutler, Glaeser and Vigdor (1999).

Geographic areas are identified two ways in these files. Where applicable, each line of data contains a 4-digit Federal Information Processing Standard (FIPS) code. These codes identify metropolitan areas; we use the codes in effect as of June 1988. For MSAs without FIPS codes, and for city-level data, we use an eight-character alphabetical code consisting of the first six letters of the city name followed by the two-letter state postal abbreviation. For example, the name code birminal refers to Birmingham, Alabama. In the case of MSAs, name codes refer to the central city.

Back to Table of Contents

Back to Segregation Data Home Page

Sample Selection Criteria

To be included in our sample, a city or MSA must have ward or tract-level data available in a given year. In 1890, cities with over 25,000 inhabitants had ward reports. From 1900 to 1940, the population cutoff was 50,000. Tract reporting began with a select group of large cities in 1940 and 1950. Beginning in 1960, tracts are reported for most MSAs. Note that the number of MSAs has increased substantially since then.

Because segregation measures are most meaningful when the black population is sizable, we sample only cities or MSAs with at least 1,000 blacks. The following table describes the resulting sample.

Year	Area Used	Geographic Subunit	Sample Size
1890	City	Ward	60
1900	City	Ward	54
1910	City	Ward	72
1920	City	Ward	90
1930	City	Ward	111
1940	City	Ward Tract	109 58
1950	City	Tract	76
1960	MSA	Tract	158
1970	MSA	Tract	211
1980	MSA	Tract	284
1990	MSA	Tract	313

Back to Table of Contents

Back to Segregation Data Home Page

Supplementary Variable Definitions

Note: Year identifiers take the place of the underline (__) in the actual data. Also note that supplementary datasets often include values for cities that do not have segregation indices for the given year.

If your browser does not support tables follow this link.

Variable Name	Mnemonic	Years Available	Notes
Population	POP__	All	--
Black Population	B__	All	--
Foreign Born Population	FB__	1890-1980	Number of foreign born whites.
Hispanic Population	H__	1970-1990	--
Number of Wards	WARD__	1890-1940	--
Number of Tracts	TRACT__	1940-1990	--
Land Area	AREA__	1900-1940; 1970, 1990	Measured in Acres, 1900-1940; Square Miles 1970 and 1990.
Person-Weighted Density	PWDENS	1990	Equal to the density (in persons per square kilometer) of the Census tract where the "average" person lives.
Trolley Passengers Per Capita, 1902	PASSPC	1910	From 1902 Census of Streetcar Railways.
Black Servant Share, 1910	BSVTSH	1910	Share of employed blacks working as domestic servants.
Growth in Urban Mileage, 1950-1960	GUM	1970	Measures the increase in miles of state-maintained roads within urban areas. This is a state-level variable.
Number of Governments, 1962	NGOV62	1990	From 1962 Census of Governments; municipal and township governments only.
Percent of Revenue from Intergovernmental Transfers, 1962	REVIG62	1990	From 1962 Census of Governments.
Median Household Income	MEDINC	1990	From 1990 Census
Manufacturing Share	MANSHR	1990	Percent of labor force employed in manufacturing.
Income Segregation	INCSEG	1990	Dissimilarity Index using high and low income households.
Black Income Segregation	BINCSEG	1990	Dissimilarity Index using high and low income black households.
Educational Exposure	EDUCEX	1990	Measures black exposure to persons who have attended some college.
Relative Rate of Single Motherhood	SINGMOM	1990	Difference between black and nonblack rates. Based on women between the ages of 40 and 60.
Male Education	MEDUC	1990	Difference between black and nonblack share of college attendees. Based on men between the ages of 40 and 60.
Time to Work	TTWORK	1990	Difference between average black and nonblack commuting time, in minutes.
Cost of Living Index	CSTINDEX	1990	Imputed for 59 MSAs, based on income, population, and region.

Additional variables found in the ward and tract data:

Variable Name	Mnemonic	Years Available	Notes
City Indicator	CITYFLAG	1890-1950	When equal to 1, the line contains city totals rather than individual ward/tract values. No city totals available after 1950.
Native White, Native Parentage	NNP	1890-1930	--
Native White, Foreign or Mixed Parentage	NFP	1890-1930, 1960-1970	--
Native White	NTVW	1940-1950	--
White Population	WHITE	1970-1990	--
Other Race	OTHER	1890-1950	--
New Immigrants	NEWIMM	1910-1920	Individuals born in Southern/Eastern European countries.
Old Immigrants	OLDIMM	1910-1920	Individuals born in Northern European countries.
Other Immigrants	OTHIMM	1910-1920	Individuals born in foreign countries outside Europe.
Tract Area	TAREA	1990	Measured in square kilometers.
Tract Longitude	LONG	1990	--
Tract Latitude	LAT	1990	--