Purpose: Key considerations in designing multilevel experimental studies are to efficiently use resources and to determine the sample size allocation such that designs have adequate statistical power. The utility of optimal sampling and power analysis results depends on accurate information about design parameters, such as intraclass correlations…

Background: There is an increased focus on randomized trials for proximal behavioral outcomes in early childhood research. However, planning sample sizes for such designs requires extant information on the size of effect, variance decomposition, and effectiveness of covariates. Objectives: The purpose of this article is to employ a recent large…

Little research has explored the impact of teacher behavior in the relationship between classroom movement breaks and student outcomes. The authors' primary purpose was to explore teacher behavior during classroom movement breaks to determine if teacher behavior served as a moderating variable in the relationship between physical activity and…

Based on a one-year longitudinal experimental study with 3,782 kindergarten school children across 15 countries, this article examines the association between prayer and happiness. Results show that the post-test scores on the faces scale were higher for the participant group who had taken the prayer lessons vis-à-vis the comparison group.…

Purpose: This prospective study was designed to evaluate psychometric properties of the Activity Choice Index (ACI), a measure for assessing one's choice to engage in more effortful, physically active behaviors in the course of daily routines over less-demanding, sedentary behaviors, in a sample of overweight women. Method: The sample included 192…

Most of the individual difference variance in the population is found "within" families, yet studying the processes causing this variation is difficult due to confounds between genetic and nongenetic influences. Quasi-experiments can be used to test hypotheses regarding environment exposure (e.g., timing, duration) while controlling for…

There is growing interest in the use of a multi-tiered system of supports framework to address issues related to school climate and bullying. Positive Behavioral Interventions and Supports (PBIS) is one such model that has received considerable attention; however, nearly all of the extant literature has focused on elementary and middle schools,…

The current study examines classroom-level peer behavioral regulation skills and their implications for children's school readiness outcomes. Specifically, this study will answer the following research questions: (1) Is the average level of peers' behavioral regulation skills in a classroom in the fall associated with growth in children's school…

In 2004, the U.S. Department of Education's Institute of Education Sciences contracted with Mathematica Policy Research to conduct a large-scale evaluation of comprehensive teacher induction. The purpose of the study was to determine whether augmenting the set of services districts usually provide to support beginning teachers with a more…