The purpose of this study is to explore the views of autistic adults on randomised controlled trials, specifically on processes such as randomisation and blinding, to understand the barriers and facilitators for recruiting autistic people to randomised controlled trials involving medications. We conducted one-to-one interviews with 49 autistic…

Although experimental evaluations have been labeled the "gold standard" of evidence for policy (U.S. Department of Education, 2003), evaluations without an analysis of costs are not sufficient for policymaking (Monk, 1995; Ross et al., 2007). Funding organizations now require cost-effectiveness data in most evaluations of effects. Yet,…

Traditionally, cluster randomized controlled trials are analyzed with the average intervention effect of interest. However, in populations that contain higher degrees of heterogeneity or variation may differ across different values of a covariate, which may not be optimal. Within education and social science contexts, exploring the variation in…

During the COVID-19 pandemic, the race to find an effective vaccine or treatment saw an 'extraordinary number' of clinical trials being conducted. While there were some key success stories, not all trials produced results that informed patient care. There was a significant amount of waste in clinical research during the pandemic which is said to…

Sample size determination in multilevel randomized trials (MRTs) and multilevel regression discontinuity designs (MRDDs) can be complicated due to multilevel structure, monetary restrictions, differing marginal costs per treatment and control units, and range restrictions in sample size at one or more levels. These issues have sparked a set of…

In the complex world of educational policy, causal inferences will be debated. As we review non-experimental designs in educational policy, we focus on how to clarify and focus the terms of debate. We begin by presenting the potential outcomes/counterfactual framework and then describe approximations to the counterfactual generated from the…

Background: The COVID-19 pandemic and the subsequent public health response led to an unprecedented disruption in educational instruction in the U.S. and around the world. Many schools quickly moved to virtual learning for the bulk of the 2020 spring term and many states cancelled annual assessments of student learning. The 2020-21 school year…

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)…

Cluster Randomized Trial (CRT) designs are inherently multilevel and reflect the hierarchical structure of schools and the wider education system. To capture this multilevel nature, CRTs are commonly analysed using multilevel (or hierarchical) linear models. It is fairly common for CRT designs and analyses to include school and individual/pupil…

Experimental studies are often employed to test the effectiveness of teaching innovations such as new pedagogy, curriculum, or learning resources. This article offers guidance on good practice in developing research designs, and in drawing conclusions from published reports. Random control trials potentially support the use of statistical…

Using an RD design provides statistically robust estimates while allowing researchers a different causal estimation tool to be used in educational environments where an RCT may not be feasible. Results from External Evaluation of the i3 Scale-Up of Reading Recovery show that impact estimates were remarkably similar between a randomized control…

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…

The What Works Clearinghouse (WWC) maintains design standards to identify rigorous, internally valid education research. As education researchers advance new methodologies, the WWC must revise its standards to include an assessment of the new designs. Recently, the WWC has revised standards for two emerging study designs: regression discontinuity…

Owing to unique features of their design, cluster randomized trials complicate the interpretation of standard ethics guidelines. The recently published Ottawa statement on the ethical design and conduct of cluster randomized trials provides researchers and research ethics committees with detailed guidance on the design, conduct, and review of…

Despite recent emphasis on the use of randomized control trials (RCTs) for evaluating education interventions, in most areas of education research, observational methods remain the dominant approach for assessing program effects. Over the last three decades, the within-study comparison (WSC) design has emerged as a method for evaluating the…