The index of dissimilarity measures the evenness with which two distinct groups are spread across the component geographic units of a city or metropolis. The index would take on its maximum value of 100 were all members of each group confined to geographic units made up exclusively of their own group; i.e., total Apartheid. If individuals were randomly assigned to place of residence, the index of dissimilarity would approach its minimum value of zero.
SOURCE: www.albany.edu/mumford/census