Randomized experiments are often considered the strongest designs to study the impact of educational interventions. Perhaps the most prevalent class of designs used in large scale education experiments is the cluster randomized design in which entire schools are assigned to treatments. In cluster randomized trials (CRTs) that assign schools to…

"Curiosity Corner" is an early childhood curriculum emphasizing children's language and literacy skills. It comprises two sets of 38 weekly thematic units--one for three-year-olds and one for four-year-olds. Program staff conduct daily lessons using sequential daily activities. One study of "Curiosity Corner" meets the What…