Research Findings: As policymakers expand access to preschool, the sociodemographic composition of preschool classrooms will become increasingly important. These efforts may create programs that increase the concentration of children from low-income families or, alternatively, foster the creation of socioeconomically diverse preschool classrooms.…

Many educational Randomized Controlled Trials (RCTs) collect baseline versions of outcome measures (pretests) to be used in the estimation of impacts at posttest. Although pretest measures are not necessary for unbiased impact estimates in well executed experimental studies, using them increases the precision of impact estimates and reduces sample…

The development of imitation during the second year of life plays an important role in domains of sociocognitive development such as language and social learning. Deficits in imitation ability in persons with autism spectrum disorder (ASD) from toddlerhood into adulthood have also been repeatedly documented, raising the possibility that early…