The measurement of occupational segregation and its component dimensions

The paper reviews different approaches to, and current knowledge of the measurement of occupational segregation, using the case of gender segregation. It shows that most popular segregation ‘indices’ are actually statistics of association in a 2x2 table, often with distorting weightings. The dimensions of segregation comprise a vertical dimension measuring inequality and an orthogonal horizontal one measuring difference without inequality. Together, the dimensions make up segregation as generally understood; so segregation and its dimensions require consistent measurements. Conditions for suitable measures are considered, and the limitations of the various measures noted. The alternative conception of segregation, where all occupations are treated as though they were the same size, is shown to be seriously flawed. The most useful measures are selected and shown to be related as Lorenz curves. Since all segregation measures vary with the number of occupations considered, standardisation on 200 occupations is introduced for the chosen measures.