Selective schooling systems, and their grammar schools, continue to be a prominent policy issue in England. Questions are asked such as, should grammar schools be reintroduced across the country? Should they be expanded where they currently exist? These questions are passionately debated and continue to be controversial. Popular stories in the press are of the form “I went to a grammar school and look how well I’m doing now”. However, whilst interesting and often inspiring, these anecdotes are not a basis for policy.