To assess the effects of streaming and mixed ability teaching in the early years of schooling on later schooling, including friendship, attitude, subject choice, examination success and career aspirations. Variables Data collected includes students' personal information on entry to school (date of birth, sex, primary school, socio-economic group), results of tests in early years of school (maths, science, languages, VRQ, attitudes, creativity, and later measurements including ASI, SSCS, differential aptitudes, subject choices, friendship groups, O and CSE results, 6th form choice.