The Effective Provision of Pre-school Education (EPPE) project explores the impact of pre-school centre provision on young children's cognitive progress and their social/behavioural development. The EPPE study was commissioned and funded by the DfES. The research has tracked a large sample of over 2700 young children and analysed cognitive attainment and progress and social behaviour at the end of Year 2 (age 7 years plus). Earlier reports have examined cognitive attainment and social/behavioural development over the pre-school period. This paper investigates attainment, progress and social/behavioural development from entry to reception classes (age rising 5 years) until the end of Year 1 in primary school, when children were age 6 years plus.