The first is the Duncan index or index of dissimilarity (see methodological annex), which reflects the proportion of students from the minority group, classified in this case as poor, who would have to switch school type to be distributed homogeneously across the different schools. Values range from 0 to 1, with 0 representing nil segregation and 1 maximum segregation. The second index is the index of isolation, which can be interpreted as the likelihood of a member of the minority group (students from the first quintile in this case) coming across a member of their own group at school (see methodological annex).