Measuring spatial concentration: the use of threshold profiles

The measurement of spatial pattern is often undertaken using one of a number of single-number indices, such as the Gini coefficient, which may not illuminate certain aspects of the pattern involved -- especially the degree to which the members of the reference group are spatially concentrated. We suggest an alternative approach based on a concentration profile which shows the degree to which a group is spatially concentrated according to a range of thresholds. This is illustrated with data on male unemployment in England and Wales in 1991, which also shows the importance of spatial scale to the study of concentrations and, potentially, to the formulation of spatially focused public policies.