Are class size and teacher characteristics associated with cognitive outcomes in early grades?

ABSTRACT This study examines the associations between class size, teacher characteristics, and children’s academic achievement in mathematics, reading, and science using a recent, large-scale, longitudinal dataset. Individual fixed effects models, which control for observed and unobserved time-invariant student variables, were employed to conduct analysis of longitudinal data from the Early Childhood Longitudinal Study – Kindergarten in 2011 (ECLS-K:2011). Results suggest that reducing class size is associated with increases in reading and mathematics scores, but not in science scores. Non-linear class size effects were also detected and were more pronounced in reading achievement. Class size estimates were small in magnitude. A five-student decrease in class size corresponds to nearly a 0.01 standard deviation increase in mathematics and reading scores. None of the teacher characteristics were related to children’s cognitive outcomes. Finally, changing schools from grade to grade has a significant negative effect on children’s reading achievement.