This proposed panel brings together three papers that aim to advance evaluation methods to isolate the causal effects of the early care and education environment. The papers draw on two important data sets: (1) the experimental evaluation data from the Head Start Impact Study (HSIS); and (2) the Birth cohort of the Early Childhood Longitudinal Study (ECLS-B). First, as the only large-scale randomized experiment in Head Start history, the HSIS reported benefits of Head Start at the 12-month follow-up, while few benefits were maintained thereafter. Children in both the treatment and control groups experienced a mixture of alternative care settings, and varying levels of quality across those settings, with some staying at home as well. Children’s experiences in the treatment and control group were quite heterogeneous, and two papers on this panel aim to tease out the effects of Head Start quality, on the one hand, and care arrangement, on the other. The HSIS included a nationally representative sample of 4,667 three- and four-year-old children in 84 sites, with rich follow-up data through the children’s third grade year. The papers take a similar approach to analyzing what would otherwise be considered “endogenous” subgroups (per Orr, 1999) to consider the causal pathways of influence that stemmed from having been randomly assigned to have access to the Head Start program. Second, the Birth cohort of the Early Childhood Longitudinal Study (ECLS-B) is a nationally representative longitudinal survey of approximately 11,000 children born in 2001, and it has been used to explore a host of research questions pertaining to the influences on children’s development and well-being. The third paper included here suggests a creative instrumental variables approach to estimating how the type of child care impacts children. In brief, this panel will address methodological challenges and suggest some innovative approaches to informing what we know about the influence of early education and care on children’s development in the cognitive, health, behavioral and social spheres, both in the short- and long-term.