Skill variability within play groups and response to a preschool block play intervention

Children's response to play-based interventions in early childhood may depend on the variability of children's skills in the play group to which they are assigned. We investigated the relation between pretest play group variability and responsiveness to intervention using data from a preschool block play intervention for children from low-income backgrounds. Preschoolers (N = 142, M _age = 52.76 months) from two Midwestern states in the United States participated in the 8-week intervention, randomly assigned to either a free play or semi-structured condition. We tested whether pretest group variability in math, spatial, and self-regulation skills within intervention groups related to change from pre- to post-test, and whether any effects of group variability were moderated by the group's average skill-level or the type of block play they engaged in. Group variability was only related to change for self-regulation skills, such that more homogeneous groups grew more over time in behavioral self-regulation and complex planning skills. Effects were not moderated by group initial average skill level or type of block play. We unpack these findings and suggest future areas of research for early childhood play-based interventions.