these programmes commonly allow parents to report several school preferences to a central enrolment point which public authorities then try to respect as much as possible while maintaining a balanced distribution of students the allocation mechanisms vary across countries and their effectiveness depends on the capacity to match parents preference for quality schools with a consistent application of priority criteria benefiting disadvantaged students oecd the student allocation mechanism also requires a certain degree of centralisation in order to prevent inefficiencies related to handling multiple registrations as well as delays on assignment and higher administrative costs