From the abstract: "The effectiveness of two professional development interventions, each designed to strengthen teacher-child interactions in preschool classrooms, was tested using a teacher-level randomized controlled trial. Georgia’s Pre-K teachers (n = 486 in 336 schools/centers) were randomly selected from specified regions and randomly assigned to one of three conditions: 1) Making the Most of Classroom Interactions (MMCI), a cohort-model where small groups of teachers met for five days of instruction and support; 2) My Teaching Partner (MTP), in which teachers worked one-on-one with a coach using cycles of videotaped observations of teaching, review, and feedback; or 3) control. Each participating teacher received a Classroom Assessment Scoring System (CLASS; Pianta, La Paro, & Hamre, 2008) visit before and after the intervention from a trained, independent, blinded observer. Post-test scores were estimated as a linear function of condition and pre-test score, using 2-level hierarchical linear models (HLMs). Findings indicated MMCI resulted in significantly higher post-test scores on Emotional Support and Instructional Support, and marginally higher post-test scores on Classroom Organization, as compared to controls. MTP resulted in significantly higher scores on Emotional Support. Findings are discussed in terms of implications for large-scale interventions to improve teacher-child interactions in early childhood programs."