When a researcher tests an educational program, product, or policy in a randomized controlled trial and detects a significant effect on an outcome, the intervention is usually classified as something that "works." When expected effects are not found, there is seldom an orderly and transparent analysis of plausible reasons why.…

Over the past 15 years, we have seen an increase in the use of cluster randomized trials (CRTs) to test the efficacy of educational interventions. These studies are often designed with the goal of determining whether a program works, or answering the what works question. Recently, the goals of these studies expanded to include for whom and under…

There are a growing number of large-scale educational randomized controlled trials (RCTs). Considering their expense, it is important to reflect on the effectiveness of this approach. We assessed the magnitude and precision of effects found in those large-scale RCTs commissioned by the UK-based Education Endowment Foundation and the U.S.-based…

Poor program implementation constitutes one explanation for null results in trials of educational interventions. For this reason, researchers often collect data about implementation fidelity when conducting such trials. In this article, we document whether and how researchers report and measure program fidelity in recent cluster-randomized trials.…

Background: It has become increasingly important to shift education research and programming from a deficit focused perspective to a positive youth development perspective in order to identify and promote factors that support students' positive functioning and outcomes. One outgrowth of positive youth development is Positive Mental Health (PMH),…

Many public and private initiatives have focused on improving prekindergarten (PK) through Grade 12 mathematics education, given that the mathematics content learned before college is foundational for later learning and college success across STEM subjects. Although decades of educational research have studied PK-12 mathematics interventions, the…

Since the 1990s, there have been repeated calls for the systematic use of randomised controlled trials (RCTs) to inform educational decision-making. The advent of the Education Endowment Foundation (EEF) -- described as England's What Works Centre for Education -- in 2011 has made this a reality in England: by 2020, over a third of English schools…

Educational stakeholders are keen to know the magnitude and importance of different interventions. However, the way evidence is communicated to support understanding of the effectiveness of an intervention is controversial. Typically studies in education have used the standardised mean difference as a measure of the impact of interventions. This…

School-based evaluations of interventions are increasingly common in education research. Ideally, the results of these evaluations are used to make evidence-based policy decisions for students. However, it is difficult to make generalizations from these evaluations because the types of schools included in the studies are typically not selected…

Background: The Education Endowment Foundation (EEF) is an independent charity that was established in 2011 with the explicit aim of breaking the link between family income and educational achievement in England. Over the seven years since its inception, EEF has contributed to the existing evidence base by funding over one hundred randomised…

Pathblazer is a supplemental, online intervention program that helps struggling learners in grades K-8 achieve grade-level proficiency in mathematics and reading. It offers students individualized learning progression paths with fun, motivating content that addresses skill and concept gaps. Using existing student data or results from a screener,…

Background: Stigmatizing attitudes toward mental illness and low mental health literacy have been identified as links to social adversity, and barriers to seeking and adhering to treatment among adolescents suffering from mental illness. Prior research has found that it is possible to improve these outcomes using school-based mental health…

Research has shown that teacher effectiveness is the most important school-based factor that influences student outcomes, including student achievement. Studies have also shown that there is substantial variation in teacher effectiveness, such that some teachers improve student outcomes at a much faster rate than others. The strong influence of…

Based on the experience of evaluating 2 cross-age peer-tutoring interventions, we argue that researchers need to pay greater attention to causal mechanisms within the context of school-based randomised controlled trials. Without studying mechanisms, researchers are less able to explain the underlying causal processes that give rise to results from…

Until recently, asking K-12 students--who spend hundreds of hours with their teachers annually--to weigh in on their teachers' performance was considered taboo. Many have questioned students' capacities to provide reliable, fair feedback on teaching quality. Media outlets report that teacher unions staunchly oppose integrating student feedback in…