The second dimension, exposure, concerns the degree of potential contact or possibility of interaction between members of the different groups within an organizational unit. Here, a group is said to be segregated if it has little likelihood of meeting members of the other groups in the organizational unit it belongs to. Primary and secondary school pupils are classified on this basis, distinguishing between the poorest (those in the first income quintile) and the rest, and divided by the type of educational establishment they attend (State or private).