Data for the City Area

    A note about boundaries

Ethnic and racial composition

Total Population Non Hispanic
Non Hispanic
Hispanic Asian Other Races
1980 3,005,072 1,299,557 1,187,905 422,063 66,200 29,347
43.2% 39.5% 14.1% 2.2% 1.0%
1990 2,783,726 1,056,048 1,074,471 545,852 98,777 8,578
37.9% 38.6% 19.6% 3.5% 0.3%
2000 2,896,016 907,166 1,068,054 753,644 136,800 30,352
31.3% 36.9% 26.0% 4.7% 1.0%
2010 2,695,598 854,717 889,783 778,862 160,206 12,030
31.7% 33.0% 28.9% 5.9% 0.4%
2020 2,746,388 863,622 818,105 819,518 213,291 31,852
31.5% 29.8% 29.8% 7.8% 1.2%

1980 1990
2000 2010 2020

Segregation: Three Measures

Index of Dissimilarity (D)
The dissimilarity index measures whether one particular group is distributed across census tracts in the metropolitan area in the same way as another group. A high value indicates that the two groups tend to live in different tracts. D ranges from 0 to 100. A value of 60 (or above) is considered very high. It means that 60% (or more) of the members of one group would need to move to a different tract in order for the two groups to be equally distributed. Values of 40 or 50 are usually considered a moderate level of segregation, and values of 30 or below are considered to be fairly low. For a more detailed explanation, click here.
Exposure Index
Another measure of residential segregation is a class of exposure indices (p*) that refer to the racial/ethnic composition of the tract where the average member of a given group lives. For example, the average Hispanic in some metropolis might live in a tract that is 40% Hispanic, 40% non-Hispanic white, 15% black, and 5% Asian.(Note that these various indices must add up to 100%.) These are presented below in two categories: exposure of the group to itself (which is called the Index of Isolation) and exposure of the group to other groups). For a more detailed explanation, click here.
Isolation Index
The isolation index is the percentage of same-group population in the census tract where the average member of a racial/ethnic group lives. It has a lower bound of zero (for a very small group that is quite dispersed) to 100 (meaning that group members are entirely isolated from other groups). It should be kept in mind that this index is affected by the size of the group -- it is almost inevitably smaller for smaller groups, and it is likely to rise over time if the group becomes larger. For a more detailed explanation, click here.
Exposure to Other Groups
Indices of exposure to other groups also range from 0 to 100, where a larger value means that the average group member lives in a tract with a higher percentage of persons from the other group. These indices depend on two conditions: the overall size of the other group and each group's settlement pattern. For a more detailed explanation, click here.


©Spatial Structures in the Social Sciences, Brown University