Differential Effects of Literacy Instruction Time and Homogeneous Ability Grouping in Kindergarten Classrooms: Who Will Benefit? Who Will Suffer?

This study challenges the belief that homogeneous ability grouping benefits high-ability students in cognitive and social-emotional development at the expense of their low-ability peers. From a developmental point of view, the authors hypothesize that homogeneous grouping may improve the learning behaviors and may benefit the literacy learning ofkindergartners at all ability levels through adaptive instruction under adequate instructional time. The benefits are expected to be more evident for mediumand low-ability children than for high-ability children. However, when instructional time is limited, low-ability children may suffer from high-intensity grouping, defined as grouping taking up a large proportion of instructional time. The authors also examine whether low-ability kindergartners develop lower self-esteem as a result of homogeneous grouping. Analyzing Early Childhood Longitudinal Study kindergarten cohort data, the authors find no overall advantage of homogeneous grouping for high-ability students. For medium-ability students' literacy growth, homogeneous grouping appears to be optimal when teachers spend more than 1 hour per day on literacy instruction; high-intensity grouping shows additional advantage for improving these students' general learning behaviors. For low-ability kindergartners, homogeneous grouping with ample instruction time seems to improve their general learning behaviors, whereas low-intensity grouping with ample instruction time seems to reduce internalizing problem behaviors. Yet for low-ability students' literacy growth, a detrimental effect of high-intensity grouping is found when instructional time is limited. These findings contradict results from past research and have important implications for educational theories and practice.