Like D, this index moves in the range [0,11, with 1 being the highest possible degree of segregation. If students were perfectly integrated by income across State and private schools, each unit would reproduce the general distribution (percentiles from 0 to 1) and the average difference between a family and the median in that family's unit would be 0.25, so that the index would take the value 0. At the other extreme, if students were perfectly segregated, each unit would contain individuals with the same income from the same percentile, and the index would take the value 1.