A comprehensive school typically describes a secondary school for pupils aged approximately 11–18, that does not select its intake on the basis of academic achievement or aptitude, in contrast to a selective school system where admission is restricted on the basis of selection criteria, usually academic performance. In England and Wales comprehensive schools were introduced as state schools on an experimental basis in the 1940s and became more widespread from 1965. They may be part of a local education authority or be a self governing academy or part of a multi-academy trust.