The level of implementation (i.e., early, late, or incomplete) was associated with stronger results. Although most Early Head Start families received some services, fewer than half were involved intensively for the full period of eligibility. Nevertheless, program families and children generally received substantially more services than those in the comparison group. With respect to outcomes, positive impacts of Early Head Start were observed on children’s cognitive development, language development, and several aspects of socio-emotional development. In addition, the assessment of Early Head Start parents demonstrated some favorable impacts on parenting outcomes (e.g., reading daily to the child) and on some aspects of progress towards self-sufficiency (education, job training activities). Early Head Start mothers were less likely to have subsequent births within two years.