Principal leadership has been widely regarded as a powerful catalyst for school improvement and student learning. This article presents a multivariate meta-analysis of 42 empirical studies, published between 2000 and 2020, that examined the effects of principal leadership on student achievement in the United States. The focus is on the conceptual…

Designing and interpreting controlled experiments are important inquiry skills addressed in many current science curricula. The relevant skills associated with the design and interpretation of controlled experiments are summarised under the term control-of-variables strategy (CVS). Research on elementary school students' CVS skills shows that they…

Cluster-randomized trials have been widely used to evaluate the treatment effects of interventions on student outcomes. When interventions are implemented by teachers, researchers need to account for the nested structure in schools (i.e., students are nested within teachers nested within schools). Schools usually have a very limited number of…

Understanding when it is appropriate to make causal inferences from a statistical result is a fundamental skill for science literacy. Prior research has concentrated on erroneous causal judgments about observational studies, but there is little research on whether people understand that experiments provide stronger justification for causal claims.…

In Single-Case Designs (SCD), the outcome variable most commonly involves some form of count data. However, statistical analyses and associated effect size (ES) calculations for count outcomes have only recently been proposed. Three recently proposed ES methods for count data are: Nonlinear Bayesian effect size (Rindskopf, 2014), Log Response…

A latent variable modeling-based procedure is discussed that permits to readily point and interval estimate the design effect index in multilevel settings using widely circulated software. The method provides useful information about the relationship of important parameter standard errors when accounting for clustering effects relative to…

Currently the design standards for single case experimental designs (SCEDs) are based on validity considerations as prescribed by the What Works Clearinghouse. However, there is a need for design considerations such as power based on statistical analyses. We compute and derive power using computations for (AB)[superscript k] designs with multiple…

Background: Special education services are individualized supports provided to students with disabilities (SWD) that should help them make appropriate educational progress given their abilities, educational needs, and goals (Endrew F. v. Douglas County School District, 2017). Concerns about the benefits of these services have emerged given the…

This study utilizes a correlational research design to identify the relationship, if any, between institutional and external support of research and development (R&D) at an R1 University Carnegie Classification of Institutions of Higher Education R1: Very High Research Activity Doctoral University in the southeastern United States of America.…

When higher education students are assessed multiple times, teachers need to consider how these assessments can be combined into a single pass or fail decision. A common question that arises is whether students should be allowed to take a resit. Previous research has found little to no clear learning benefits of resits and therefore suggested they…

In cluster randomized evaluations, a treatment or intervention is randomly assigned to a set of clusters each with constituent individual units of observations (e.g., student units that attend schools, which are assigned to treatment). One consideration of these designs is how many units are needed per cluster to achieve adequate statistical…

In cluster randomized evaluations, a treatment or intervention is randomly assigned to a set of clusters each with constituent individual units of observations (e.g., student units that attend schools, which are assigned to treatment). One consideration of these designs is how many units are needed per cluster to achieve adequate statistical…

Preschoolers' prosocial behaviours support healthy interpersonal relationships as a component of their social adjustment process. Although several studies have found links between parental marital characteristics and preschoolers' prosocial behaviours, these conclusions were divisive. Therefore, a meta-analysis was conducted to clarify the…

We examine how the politics of knowledge production limit research on the relationship between immigration status and social inequality. We centre the practices of methodological nationalism in Canada, a traditional country of permanent immigration in which temporary migration has become a core feature of the immigration system. In this case,…

Many experimental designs in educational and behavioral research involve at least one level of clustering. Clustering affects the precision of estimators and its impact on statistics in cross-sectional studies is well known. Clustering also occurs in longitudinal designs where students that are initially grouped may be regrouped in the following…