To plan cluster-randomized trials with sufficient statistical power to detect intervention effects on student achievement, researchers need multilevel design parameters, including measures of between-classroom and between-school differences and the amounts of variance explained by covariates at the student, classroom, and school level. Previous…

Multilevel modeling (MLM) is frequently used to detect cluster-level group differences in cluster randomized trial and observational studies. Group differences on the outcomes (posttest scores) are detected by controlling for the covariate (pretest scores) as a proxy variable for unobserved factors that predict future attributes. The pretest 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.…

This study addresses the effectiveness of "Everyday Mathematics" (EM), a widely used core mathematics curriculum that reflects over two decades of National Science Foundation (NSF)-sponsored research and development studies (Klein, 2007; National Research Council, 2004) and aligns well with recommended policies and practices by the…

The purpose of this replication study was to examine the impact of the Teacher Study Group (TSG) professional development in vocabulary on first-grade teachers' knowledge of vocabulary instruction and observed teaching practice, and on students' vocabulary knowledge. Sixty-two schools from 16 districts in four states were randomly assigned to…

A variety of computerized interactive learning platforms exist. Most include instructional supports in the form of problem sets. Feedback to users ranges from a single word like "Correct!" to offers of hints and partially to fully worked examples. Behind-the-scenes design of such systems varies as well --from static dictionaries of…

This is an extended conference proceedings report [Long Paper] based on a shorter contributed report at the same conference. A variety of computerized learning platforms exist. In mathematics, most include sets of problems to complete. Feedback to users ranges from a single word like "Correct!" to offers of hints and partially- to…

I discuss three common practices that obfuscate or invalidate the statistical analysis of randomized controlled interventions in applied linguistics. These are (a) checking whether randomization produced groups that are balanced on a number of possibly relevant covariates, (b) using repeated measures ANOVA to analyze pretest-posttest designs, and…

This study examined the hypothesis that assisted writing during reading improves reading comprehension. The hypothesis was derived from sociocognitive and constructivist theory and research and implemented in the form of a curricular intervention called Writing Intensive Reading Comprehension after its main feature of bringing together reading…

Reading comprehension in the content areas is a challenge for many middle grade students. Text structure-based instruction has yielded positive outcomes in reading comprehension at all grade levels in small and large studies. The text structure strategy delivered via the web, called Intelligent Tutoring System for the Text Structure Strategy…

As part of the 2010 economic stimulus, a $55 million "Investing in Innovation" (i3) grant from the US Department of Education was awarded to scale up Reading Recovery across the nation. This paper presents the final round of results from the large-scale, mixed methods randomized evaluation of the implementation and impacts of Reading…

This study addresses the effectiveness of a widely used core reading program that reflects the research-based practices recommended by the National Reading Panel. This and other similar programs are increasingly used to prevent reading difficulties and ensure that all children are reading at or above grade level by the end of third grade.…

Many preschool language-focused interventions attempt to boost language and literacy skills in young children at risk in these areas of development, though the long-term effects of such interventions are not well-established. This study investigated kindergarten language and reading skills, specifically the subcomponents of vocabulary, decoding,…

The present study evaluates the effectiveness of Check & Connect (C&C) in a randomly assigned sample of students who were all receiving Communities in Schools (CIS) services. The research questions for the study include: Are there differences in attendance, academics, and behavior for CIS students who also receive C&C compared to…

The capacity of the field to conduct power analyses for group randomized trials (GRTs) of educational interventions has improved over the past decade (Authors, 2009). However, a power analysis depends on estimates of design parameters. Hence it is critical to build the empirical base of design parameters for GRTs across a variety of outcomes and…