Plausible competing developmental models show similar or identical structural equation modeling model fit indices, despite making very different causal predictions. One way to help address this problem is incorporating outside information into selecting among models. This study attempted to select among developmental models of children's early…

This study investigates the impact of Education Endowment Foundation (EEF)-funded trials on pupils eligible for free school meals. Although similar analysis is conducted during each individual evaluation, this report conducts a meta-analysis using data from 88 trials and over half a million pupils to reach conclusions. The report contributes to…

Principals are the second-largest school-based contributor to K-12 students' academic progress. However, there is little research evaluating whether efforts to develop principals' skills improve school effectiveness. We conducted randomized controlled trial studies of the impacts of a professional development program called the Executive…

Community colleges are essential for United States higher education, but their students have low retention and graduation rates. Community college students assigned to mathematics remediation are particularly unlikely to graduate. Corequisite remediation (college-level coursework with additional support) has shown short-term increased student…

The gold-standard for evaluating the effect of an educational intervention on student outcomes is running a randomized controlled trial (RCT). However, RCTs may often be small due to logistical considerations, and resulting treatment effect estimates may lack precision. Recent methods improve experimental precision by incorporating information…

Analyses were conducted with second graders, drawn from an ongoing multi-cohort randomized controlled trial (RCT), who had been identified for RCT entry based on comorbid reading comprehension and word-problem solving difficulty. To estimate pandemic learning loss, we contrasted fall performance for 3 cohorts: fall of 2019 (pre-pandemic; n = 47),…

Researchers often include covariates when they analyze the results of randomized controlled trials (RCTs), valuing the increased precision of the estimates over the potential of inducing small-sample bias when doing so. In this paper, we develop a sufficient condition which ensures that the inclusion of covariates does not cause small-sample bias…

Background/Context: Early childhood education research has consistently found evidence of immediate, positive effects on developmental outcomes. Despite these strong initial benefits, follow-up analyses often reveal that these effects fadeout in the years following participation (e.g., Bailey et al., 2017, Clements et al., 2013; Lipsey et al.…

Purpose: Key considerations in designing multilevel experimental studies are to efficiently use resources and to determine the sample size allocation such that designs have adequate statistical power. The utility of optimal sampling and power analysis results depends on accurate information about design parameters, such as intraclass correlations…

Empirical evidence exists that enhancing students' language can promote the mathematics learning of multilingual students at risk, whereas other target groups (e.g., monolingual students, successful students, both with diverse academic language proficiency) have hardly been considered. This cluster-randomized controlled trial (N = 589)…