Social Segregation in Irish Schools

Social segregation in schools refers to the uneven distribution across schools of children from different socio-economic backgrounds. Why should we care? One simple reason is that not all schools are as good as others so if particular groups are concentrated in "good schools" (however that is measured) that has implications for inequality. Of course if low socio-economic status (SES) children were concentrated in the best schools then this would tend to mitigate inequality but in reality the opposite is likely to be the case and hence education could act to exacerbate inequalities with well-off children's advantage increasing, or at least being maintained, as a result of their schooling. It has also been argued that high levels of social segregation are bad for social cohesion.
A recent paper provides valuable evidence on this for a wide range of countries including Ireland. They calculate two measures of social segregation, a dissimiliarity index D and Hutchens H index. Each ranges between 0 (no social segregation with each school's distribution of SES the same as that of the country) and 1 (where each school consists of children with the same SES). The H index has the advantage that it is additively decomposable: the index can be written as a weighted average of the score for sub-groups (e.g. private vs. public schools).
Of the 27 countries (using PISA 2000,2003), by far the highest level of segregation is in Hungary. Japan and Sweden have the lowest levels of segregation. In general countries with "tracking", separate academic and vocational school systems, have high levels of segregation. Ireland actually does pretty well, having the 7th lowest level of social segregation. Northern Ireland, by contrast, has the 11th highest level of segregation.

Social segregation in secondary schools:how does England compare with other countries?
Stephen P. Jenkins, John Micklewright and Sylke V. Schnepf
Oxford Review of Education , 34(1) February 2008, 21–37