dissimilarity, index of A statistic used to measure the overall difference between two percentage distributions. It is calculated by summing the differences between the numbers in each pair of corresponding values and dividing by 2. The result lies in the range 0 to 100; is always positive; and indicates the proportion of cases that would need to be reallocated in order to make the two distributions the same. Dissimilarity indices are often reported in studies of racial and occupational segregation. In studies of social mobility they can be used to summarize the difference between pairs of marginal distributions (across nations, across the sexes, comparing class of origin and class of destination within one country, and so on). For examples see Gordon Marshall et al. , Against the Odds? (1997
).

index of dissimilarity See DISSIMILARITY, INDEX OF.