The Congressionally-mandated Early Head Start Research and Evaluation Project Study (EHSREP) was a rigorous longitudinal study that offered conclusive evidence of Early Head Start’s impact on a wide range of outcomes (see box on page 2). Yet, it left unexplained much of how those results were achieved. To fill this gap, our new analysis of EHSREP data looked at how service use at age 2 led to impacts for children and families at age 3, leading to two key new findings: NEW FINDING #1: At age 2, Early Head Start families report receiving many more services than the control group. NEW FINDING #2: Specific comprehensive services provided by Early Head Start lead to specific impacts for children and families. (author abstract)