. Participants The data of this study are a subset of data from a randomized controlled trial study designed to examine the impacts of a 30- week whole-group language and literacy curriculum called Read It Again-PreK (RIA; Justice & McGinty, 2010).1 The full-scaled study was implemented in 104 classrooms; all classrooms were located in rural Appalachian communities that targeted enrollment to children residing in low-income households; this included Head Start (57% of classrooms) and state-funded preschool programs (43%). The mean classroom size was 18 children (SD = 4.4). Study enrollment was made available to all children in the classrooms; 77% percent of children’s caregivers returned consent to participate in this study, representing an average of 14 children per classroom. From the consents received per classroom, between three and five children were randomly selected to participate in the study from among those meeting three criteria: the child was expected to enroll in kindergarten the following year, had no known disability, and spoke English as the primary language. Each classroom had a designated lead teacher, who provided data used in this study via completion of questionnaires and student assessments. Eighty-two percent of the lead teachers were certified to teach in early childhood education, and 98% had at least an associate’s degree. About two-thirds of the teachers reported using a commercial curriculum in their classrooms (62%). Teachers were invited to participate in the larger study at the invitation of their organization’s leadership, and provided consent only after receiving all relevant details of the study, including the use of randomization of conditions within a center to the various conditions. The dataset used for the present work contained 270 children from 61 ofthe 104 classrooms. Classrooms notincluded were those in which children’s peer interaction or problem behaviors were not assessed. Children’s gender, ethnicity, age, and social economic status are reported in Table 1. As shown in the table, the gender distribution of this sample was nearly equal, and the majority of children were white (90%). The average age of the study children was 53 months (SD = 3.2). The average years of maternal education was 12.9 years (SD = 1.5), and almost one-half of the children resided in homes in which the total family income was less than $20,000 per year.