This paper introduces a simple, quotient effect size, termed (for 'quotient'), suitable for reporting on the effectiveness of educational interventions. The quotient effect size for a pre-test-post-test design is defined as the gain score (i.e. post-test minus pre-test) for the intervention group, divided by the gain score for the control group.…

The randomized control trial (RCT) is the primary experimental design in education research due to its strong internal validity for causal inference. However, in situations where RCTs are not feasible or ethical, quasi-experiments are alternatives to establish causal inference. This paper serves as an introduction to several quasi-experimental…

Education decisionmakers need access to the best evidence about the effectiveness of education interventions, including practices, products, programs, and policies. It can be difficult, time consuming, and costly to access and draw conclusions from relevant studies about the effectiveness of interventions. The What Works Clearinghouse (WWC)…

We present an aggregation scheme that increases power in randomized controlled trials and quasi-experiments when the intervention possesses a robust and well-articulated theory of change. Intervention studies using longitudinal data often include multiple observations on individuals, some of which may be more likely to manifest a treatment effect…

Group design research studies can provide evidence to draw conclusions about "what works," "for whom," and "under what conditions" in special education. The quality indicators introduced by Gersten and colleagues (2005) have contributed to increased rigor in group design research, which has provided substantial…

Context: Assessments of baseline equivalency of intervention and control groups, "balance," play a critical role in evaluating educational interventions. The highest What Works Clearinghouse (WWC) of the Institute of Educational Studies (IES) standard for educational studies, "Meets WWC Design Standards Without Reservations,"…

Background: Information regarding how the Special Olympics programs affect volunteers' self-esteem and attitudes towards individuals with intellectual disability (ID) is limited. We conducted a quasi-experimental study to address this gap. Method: The intervention group participants (n = 120) were Chinese volunteers for the Special Olympics Eunice…

African-American boys who receive exclusionary discipline (i.e. in- or out-of-school suspensions) are overrepresented at the elementary (kindergarten through fifth grade) level. Although African-American boys comprised only 15% of the population of this school, they accounted for 70% of the exclusionary discipline incidents. This…

Purpose: The purposes of this study were to: (a) examine the impact of the Silverman and Solmon article (1998) on how researchers handle the unit of analysis issue in their field-based intervention research in physical education in the United States and summarize statistical approaches that have been used to analyze the data, and (b) provide…

Quasi-experiments are common in studies that estimate the effect of instructional interventions on student performance outcomes. In this type of research, the nature of the experimental design, the choice in assessment, the selection of comparison groups, and the statistical methods used to analyze the comparison data dictate the validity of…

The rapid advances of China's universities in major international league tables are generally believed to be an accomplishment of Project 985. A quasi-experimental study was, therefore, undertaken to test the belief and to evaluate the effectiveness of this policy intervention, using 15-year panel data between 1998 and 2013. Results from a…

We argue in this article that there are conditions in which publication of negative results can make a useful contribution. Three small-scale examinations of journal publication criteria for publishing negative results were conducted. We first reviewed 29 journals from education and school/counseling psychology to assess author submission…

The present study sought to evaluate the effects of a reading strategy instructional program on the reading competence of third-grade students. Students were instructed in fluent and strategic reading by trained research assistants in whole class settings and subsequently worked on expository text material together with peers. Their reading…

Purpose: To examine the effects on anxiety of mindfulness-based interventions (MBIs) among youth with anxiety disorders. Method: Systematic review and meta-analytic procedures were employed to synthesize experimental and quasi-experimental studies authored between 1980 and 2015. Results: The search yielded five studies from five countries…

Underlying all What Works Clearinghouse (WWC) products are WWC Study Review Guides, which are intended for use by WWC certified reviewers to assess studies against the WWC evidence standards. As part of an ongoing effort to increase transparency, promote collaboration, and encourage widespread use of the WWC standards, the Institute of Education…