We develop a theoretical and empirical basis for the design of teacher professional development studies. We build on previous work by (a) developing estimates of intraclass correlation coefficients for teacher outcomes using two- and three-level data structures, (b) developing estimates of the variance explained by covariates, and (c) modifying…

Although scalable programs, such as online courses, have the potential to reach broad audiences, they may pose challenges to evaluating learners' knowledge and skills. Automated scoring offers a possible solution. In the current paper, we describe the process of creating and testing an automated means of scoring a validated measure of teachers'…

An appropriate estimate of statistical power is critical for the design of intervention studies. Although the inclusion of a pretest covariate in the test of the primary outcome can increase statistical power, samples selected on the basis of pretest performance may demonstrate range restriction on the selection measure and other correlated…

The current study used a dyadic and coconstructive approach to examine how to embed exercises that support executive functioning into early literacy instruction to empower its effects. Using a randomized controlled trial design with 100 children, we examined the effects of dyadic activities in which children scaffolded each other's learning 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 paper presents the results of a study aimed at exploring the possibilities Twitter offers for pronunciation instruction. It investigates the potential of a Twitter-based approach based on explicit instruction and input enhancement techniques to help English Foreing Language (EFL) learners improve their pronunciation of segmental and…

We examined the relations between teachers' use of comments during book reading sessions in preschool classrooms and the vocabulary growth of children with low and moderately low language ability. Using data from a larger randomized controlled trial, we analyzed comments defined as utterances that give, explain, expand, or define. Comments were…

In the 21st century, students have access to a plethora of information. As such, the skills required to access and effectively sort through this information (information literacy skills) become ever more important for success in both academic and non-academic settings. This study sought to assess the efficacy of two educational games designed to…

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…

The present study examined the effectiveness of the oral history approach with respect to students' historical competence. A total of 35 ninth-grade classes (N = 900) in Germany were randomly assigned to one of four conditions--live, video, text, or a (nontreated) control group--in a pretest, posttest, and follow-up design. Comparing the three…

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…

Research Findings: This study investigated the association between Mexican American maternal education and socioeconomic status (SES) and child vocabulary as mediated by parental reading beliefs, home literacy environment (HLE), and parent-child shared reading frequency. As part of a larger study, maternal reports of education level, SES, HLE, and…

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…

The present study used a randomized control trial to examine the effects of a widely used multicomponent Tier 2-type intervention, Passport to Literacy, on the reading ability of 221 fourth graders who initially scored at or below the 30th percentile in reading comprehension. Intervention was provided by research staff to groups of 4-7 students…

The present study used a randomized control trial to examine the effects of a widely-used multi-component Tier 2 type intervention, Passport to Literacy, on the reading ability of 221 fourth graders who initially scored at or below the 30th percentile in reading comprehension. Intervention was provided by research staff to groups of 4-7 students…