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 of…

The purpose of this study is to investigate whether small group instruction in kindergarten widens or closes the achievement gap in mathematics between EL students and non-EL students. The first objective is to examine whether the impacts of small group instruction on math learning differ between EL kindergartners and their non-EL peers. For…

Defining causal effects as comparisons between marginal population means, this article introduces marginal mean weighting through stratification (MMW-S) to adjust for selection bias in multilevel educational data. The article formally shows the inherent connections among the MMW-S method, propensity score stratification, and…

The purpose of this study is two-fold. Firstly the authors examine, given the amount of time allocated to literacy instruction, whether homogeneous grouping helps improve class manageability over the kindergarten year and whether individual students' externalizing problem behaviors will decrease in tandem. Secondly, they investigate whether the…

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…