Effects of an early childhood educator coaching intervention on preschoolers: The role of classroom age composition

Heterogeneity in treatment effects of MyTeachingPartner (MTP), a professional development coaching intervention focused on improving teacher-student interactions, was examined for 1407 4-year-old preschoolers who were enrolled in classrooms that served children between the ages of 3 and 5. On average, there were no consistent impacts of MTP coaching on children's school performance, but there was evidence of moderation in treatment effects as a function of classroom age diversity, defined as the proportion of children who were not 4 years of age. MTP coaching improved children's expressive vocabulary, literacy skills, and inhibitory control in classrooms that served primarily 4-year-olds and were less age diverse. These effects were in large part due to MTP causing improvements in teachers' instructional support that in turn was more predictive of children's skills in less age-diverse classrooms. Results also indicated that the nature of age diversity did not matter; a greater number of 3- or 5-year-old classmates equally reduced the benefits of the MTP intervention for 4-year-olds. The sole exception occurred for receptive vocabulary, in which case, MTP was most effective in classrooms with a larger number of older (but not younger) children. Taken together, these results suggest that under the right circumstances, the benefits of professional development that improve early childhood educators' teaching practices can also translate into benefits for students.