Reading Instruction Time and Homogeneous Grouping in Kindergarten: An Application of Marginal Mean Weighting Through Stratification

Abstract

A kindergartner’s opportunities to develop reading and language arts skills are constrained by the amount of time allocated to reading instruction. In the meantime, the student’s engagement in learning tasks may increase if the instruction has been adapted to his or her prior ability through homogeneous grouping. This study investigates whether the grouping effects on kindergartners’ reading growth depend on the amount of reading instruction time and the intensity of grouping. To answer the study’s research questions requires causal inferences about concurrent multivalued instructional treatments. The authors develop a procedure of applying the method of marginal mean weighting through stratification to multilevel educational data. Results from the Early Childhood Longitudinal Study Kindergarten cohort data set lend support to the theoretical hypothesis that when teachers allocate a substantial amount of time to reading instruction, homogeneous grouping helps kindergartners to gain more in reading. The authors find no effect of homogeneous grouping when the total amount of reading time is limited. They also find that the benefit of increasing reading instruction time becomes evident only if kindergarten teachers adapt instruction through homogeneous grouping.