Classroom composition and quality in early childhood education: A systematic review

High-quality early childhood education appears to be particularly beneficial for disadvantaged children, since it may help reduce an initial achievement gap. Yet, these children are frequently enrolled in disadvantaged classrooms with lower quality levels. Thus, classroom composition and quality may be associated, but evidence is scarce. In this review, we gathered evidence regarding classroom composition indexes and their association with observed classroom quality, reported in 25 studies that met the inclusion criteria. The majority of studies were conducted in the United States, with disadvantaged samples of children. Classroom composition indexes used were mainly calculations of the percentage, proportion, and average/mean of a particular type of characteristic at the classroom level, that generally captured classroom homogeneity. Most studies focused on minority and socioeconomic status. ECERS and CLASS were the most frequently used standardized observation measures of classroom quality. Evidence suggests that in classrooms with a high concentration of children with minority status and from low income families, quality tends to be lower, particularly on the CLASS emotional and instructional support domains. Additional research, particularly outside the USA, focused primarily on the association between different types of classroom composition and ECE quality is warranted.