The Early Years Transitions and Special Educational Needs (EYTSEN) project builds on the work of the Effective Provision of Pre-School Education (EPPE) project, a major longitudinal study of a national sample of young children's progress and development through pre-school and into primary school until the end of Key Stage 1 (age 3+ to 7 years). Both the EPPE and EYTSEN research studies was funded by the DfES. The EYTSEN study explores evidence of possible special educational needs (SEN) amongst pre-school children. It uses a range of information to identify children who may be 'at risk' in terms of either cognitive or social behavioural development and investigates links with a variety of child, parent and family characteristics. It also describes variations in the policies and provision offered by different pre-school centres designed to support children with special needs.