The Programme for International Student Assessment (PISA) assesses the knowledge and skills in mathematics, reading and science of 15-year-old pupils in countries around the world. PISA is run by the Organisation for Economic Co-operation and Development (OECD), and assessment is typically undertaken every 3 years, allowing us to chart how…

The capacity of the field to conduct power analyses for group randomized trials (GRTs) of educational interventions has improved over the past decade (Authors, 2009). However, a power analysis depends on estimates of design parameters. Hence it is critical to build the empirical base of design parameters for GRTs across a variety of outcomes and…

The gold standard in making causal inference on program effects is a randomized trial. Most randomization designs in education randomize classrooms or schools rather than individual students. Such "clustered randomization" designs have one principal drawback: They tend to have limited statistical power or precision. This study aims to…