Introduction
The Head Start Impact Study is a Congressionally mandated study being conducted across 84 nationally representative grantee/delegate agencies. Approximately 5,000 newly entering 3-and 4-year old children applying for Head Start were randomly assigned to either a Head Start group that had access to Head Start program services, or to a non-Head Start group that could enroll in available non-Head Start services selected by their parents, in the community. Data collection began in fall 2002 and is scheduled to continue through 2006, following children through the spring of their 1st grade year.