Many interventions in education occur in settings where treatments are applied to groups. For example, a reading intervention may be implemented for all students in some schools and withheld from students in other schools. When such treatments are nonrandomly allocated, outcomes across the treated and control groups may differ due to the treatment…

We present experimental evidence on the impact of a multi-faceted program that integrates technology-aided instruction, teacher training and coaching, community ownership, and free primary education. Our setting is three districts in rural Zambia, where we randomly assigned the program across 30 treatment and 33 control schools. The results show…

The purpose of this study was to explore the effectiveness of a universal classroom-based social-emotional learning (SEL) program for first grade students. Forty classrooms from 13 elementary schools across 3 states participated in the trial. Teachers in classrooms randomly assigned to the implementation condition were provided with free access to…

Every year many students enter college without the math preparation needed to succeed in their desired programs of study. Many of these students struggle to catch up, especially those who are required to take remedial math courses before entering college-level math. Increasing the number of students who begin at the appropriate level of math has…

We assessed the impacts of a teacher professional development program for public and private kindergartens in the Greater Accra Region of Ghana. We examined impacts on teacher professional well-being, classroom quality, and children's readiness during one school year. This cluster-randomized trial included 240 schools (teachers N = 444; children N…

We use data from a large-scale, school-level randomized experiment conducted in 2010-2011 in public schools in Indiana. Our sample includes more than 30,000 students in 70 schools. We examine the impact of two interim assessment programs (i.e., mCLASS in Grades K-2 and Acuity in Grades 3--8) on mathematics and reading achievement. Two-level models…

The present article considers a fundamental question in evaluation research: "By how much do program effects vary across sites?" The article first presents a theoretical model of cross-site impact variation and a related estimation model with a random treatment coefficient and fixed site-specific intercepts. This approach eliminates…

In the "individually randomized group treatment" (IRGT) experimental design, individuals are first randomly assigned to a treatment arm or a control arm, but then within each arm, are grouped together (e.g., within classrooms/schools, through shared case managers, in group therapy sessions, through shared doctors, etc.) to receive…

We investigate the impact of a relatively brief cross-curricular intervention, Word Generation, on middle school students' development of taught academic vocabulary. Students (n = 8382) in forty-four middle schools in three urban districts were randomly assigned to treatment or control conditions. Treatment teachers implemented the program with…

This multiyear scale-up effectiveness study of Open Court Reading (OCR) involved approximately 4,500 students and more than 1,000 teachers per year in Grades K-5 from 49 elementary schools in seven districts across the country. Using a school-level cluster randomized trial design, we assessed the implementation and effectiveness of Open Court…

Randomized experiments are often seen as the "gold standard" for causal research. Despite the fact that experiments use random assignment to treatment conditions, units are seldom selected into the experiment using probability sampling. Very little research on experimental design has focused on how to make generalizations to well-defined…

Attending high-quality early childhood care and education (ECCE) is associated with higher cognitive and social-emotional skills, especially for children growing up in poverty, but access to high-quality ECCE is limited. This study capitalizes on the random assignment design of the Head Start Impact Study to better understand whether the…

The objective of the present study was to evaluate the extent to which students who took a computer adaptive test of reading comprehension accounting for testlet effects were administered fewer passages and had a more precise estimate of their reading comprehension ability compared to students in the control condition. A randomized controlled…

Multisite trials, in which individuals are randomly assigned to alternative treatment arms within sites, offer an excellent opportunity to estimate the cross-site average effect of treatment assignment (intent to treat or ITT) "and" the amount by which this impact varies across sites. Although both of these statistics are substantively…

Second-language learners display poorer general language skills in the language used at school than their monolingual peers, which is a concern because general language skills (vocabulary, grammar, language expression, and comprehension) provide the foundation for later academic success. In a randomized controlled trial, we examined the efficacy…