Recently, researchers have begun to employ rigorous statistical methods and developmentally-informed theories to evaluate outcomes for students retained in non-kindergarten early elementary school. However, the majority of this research focuses on academic outcomes. Gaps remain regarding retention's effects on psychosocial outcomes important to later school and life outcomes. Additionally, some psychosocial and academic outcomes and changes may be evident in the short-term, but others may have a delayed presentation. These "sleeper effects" are less well-understood, creating a need for new research focusing on longer-term outcomes. In response, the current study uses causal methods and a national dataset to investigate both academic achievement and psychosocial outcomes in early adolescence after early elementary grade retention. Using propensity score methodological approaches and informed by developmental systems theory, this study estimates the effect of early (first and second) grade retention on academic achievement and psychosocial outcomes in eighth grade: six or seven years later. The goal is to determine whether retention is an effective intervention for students struggling to meet academic standards early in their elementary schooling, and to inform the education policy and practice debate regarding the costs and benefits associated with grade retention. Data for this study are from the Early Childhood Longitudinal Study, Kindergarten Class 1998-1999 (ECLS-K; U.S. Department of Education, 2009), a nationally representative sample following a longitudinal cohort of 21,260 kindergartners until the eighth grade. The dataset includes multiple sources of data including administrator surveys, teacher assessments, direct child assessments, child questionnaires, and parent surveys. The sample is comprised of 5,586 students. The current study utilizes a quasi-experimental, longitudinal approach, and propensity score methodology to estimate the effect of early grade retention on academic and psychosocial outcomes in the middle grades. At the time of this report, analyses are being conducted, and formal results are forthcoming. Tables are appended.