Ghettos of the mind: the empirical behaviour of indices of segregation and diversity

Summary.  The effect of immigration on social cohesion is a political issue, expressed as a fear that racially skewed residential patterns represent ghettos which prevent integration. Residential patterns have been measured by indices of segregation. The range of indices is reviewed in the paper and measured empirically for England and Wales by using census data for 1991 and 2001, including a new index of migration dispersal. There has been an increase in residential mixing as a result of growing minority populations and their more even spread across localities. These two trends are identified by two commonly used indices of segregation which are moving in opposite directions for the most recent immigrant groups. The sensitivity of each index to modifiable area boundaries makes them unsuitable for evaluation of cities' relative performance. The residential patterns of cities after immigration are more clearly understood by using demographic measures of migration and age structure.