The increasing availability of data from multi-site randomized trials provides a potential opportunity to use instrumental variables methods to study the effects of multiple hypothesized mediators of the effect of a treatment. We derive nine assumptions needed to identify the effects of multiple mediators when using site-by-treatment interactions…

Attrition occurs when members of the initial research sample are not part of the final analysis sample, such as due to missing data or leaving the study. Both the overall sample attrition and the differences in attrition between the groups can affect the statistical equivalence of the sample and create potential for bias. The WWC has given careful…

Background: Students of clinical psychology and medicine experience high levels of mental distress and low levels of life satisfaction. Using adaptive coping strategies can modify the negative effect of stressors on health. Mindfulness, it has been claimed, more adaptive coping with stress, yet few studies have investigated whether mindfulness…

The 1990 Individuals with Disabilities Education Act (IDEA) reauthorization introduced transition mandates that included a "student involvement in transition planning" requirement, creating an emphasis on promoting such involvement so as to enhance the self-determination of students with disabilities and positive transition-related…

Randomized experiments are commonly used to evaluate if particular interventions improve student achievement. While these experiments can establish that a treatment actually "causes" changes, typically the participants are not randomly selected from a well-defined population and therefore the results do not readily generalize. Three…

Recent federal legislation, such as the "No Child Left Behind Act" of 2001 and the "Education Sciences Reform Act (ESRA)" of 2002, has insisted that educational evaluations use rigorous research designs with quantitative outcome measures. In particular, the Institute of Education Sciences (IES) at the U.S. Department of…

Researchers are increasingly using comparative interrupted time series (CITS) designs to estimate the effects of programs and policies when randomized controlled trials are not feasible. In a simple interrupted time series design, researchers compare the pre-treatment values of a treatment group time series to post-treatment values in order to…

One purpose of education research is to develop and rigorously evaluate the effectiveness of programs for supporting students' learning and achievement. The Institute of Education Sciences has amplified that purpose (Shadish & Cook, 2009) and attempted to improve the methodological standards for conducting such work--primarily through the What…

We report on an effectiveness evaluation of the Youth Empowerment Solutions (YES) program. YES applies empowerment theory to an after-school program for middle school students. YES is an active learning curriculum designed to help youth gain confidence in themselves, think critically about their community, and work with adults to create positive…

Background: In England, there is a growing need to improve the lives of secondary school students who are defined as disadvantaged and to support these students in their attainment and attitudes to secondary school science. Purpose: This paper reports on a project designed to support students from disadvantaged backgrounds by pairing them with…

We present results of an experimental study of an urban, museum-based science teacher PD programme. A total of 125 teachers and 1676 of their students in grades 4-8 were tested at the beginning and end of the school year in which the PD programme took place. Teachers and students were assessed on subject content knowledge and attitudes towards…

Open Educational Resources (OER) can offer educators the necessary flexibility for tailoring educational resources to better fit their educational goals. Although the number of OER repositories is growing fast, few studies have been conducted to empirically test the effectiveness of OER integration in the classroom. Furthermore, very little is…

Background: Studies have revealed that overweight adults with type 2 diabetes have low rates of physical activity and are resistant to change. Purpose: The purpose of this study was to use construct validation of intervention methods to examine the impact of a 4-week behavioral intervention on the use of self-regulation skills for physical…

This study examined the effects of video-based cooperative, competitive and individualized instructional strategies on the performance of senior secondary schools' students in geometry in Nigeria. It also examined the influence of gender on students' achievement. Pretest, posttest, experimental control group design was adopted for this study.…

A wide and rich body of literature has identified the family as the key context influencing children's development. In response, school districts and policymakers have sought to engage parents in children's learning, particularly low-income families. Meta-analyses conclude that efforts to engage low-income parents do improve students' academic…