Isolation is a segregation measure referring to the degree of potential contact, or the possibility of interaction, between people of the same racial group. For instance, the black isolation index provides the average proportion of neighbors that are black, for the average neighborhood where blacks live.
Racial groups refer to people who indicated they were of specified race
"alone." Excludes those specifying two or more races. Indices in metro
areas with small numbers of specified racial/ethnic groups should be
used with caution.
U.S. Census Bureau, 2000 Census, Summary File 1 and 2010 Redistricting File.