Programs that improve teaching effectiveness represent a core strategy to improve student educational outcomes and close student achievement gaps. This article compiles empirical values of intraclass correlations for designing effective and efficient experimental studies evaluating the effects of these programs. The Early Childhood Longitudinal…

This paper assesses the impact of welfare reform's parental work requirements on low-income children's cognitive and social-emotional development. The identification strategy exploits an important feature of the work requirement rules--namely, age-of-youngest-child exemptions--as a source of quasi-experimental variation in first-year maternal…

In observational studies, selection bias will be completely removed only if the selection mechanism is ignorable, namely, all confounders of treatment selection and potential outcomes are reliably measured. Ideally, well-grounded substantive theories about the selection process and outcome-generating model are used to generate the sample of…

The introduction to this Special Topic Collection has two parts. To provide background and context for the articles in the collection, Part 1 tells the story of the Early Childhood Longitudinal Study program at the National Center for Education Statistics. It offers an abridged history of this program and describes the designs of the two national…

Children participating in kindergarten programming across the United States are expected to perform at a higher level than ever before. Many of these children are unprepared and developmentally unready for the academic tasks that await them. Researchers have shown that an older age at the start of kindergarten is a predictor of academic…

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…

This study examined the effect of participation in the Home Instruction for Parents of Preschool Youngsters program on the school readiness of children born to teenage mothers versus children born to traditional-age mothers participating in the Home Instruction for Parents of Preschool Youngsters program. A 45-item survey was collected from the…

Many educational Randomized Controlled Trials (RCTs) collect baseline versions of outcome measures (pretests) to be used in the estimation of impacts at posttest. Although pretest measures are not necessary for unbiased impact estimates in well executed experimental studies, using them increases the precision of impact estimates and reduces sample…