Randomized experiments are a strong design for establishing impact evidence because the random assignment mechanism theoretically allows confidence in attributing group differences to the intervention. Growth of randomized experiments within educational studies has been widely documented. However, randomized experiments within education have…

Background: The emergence of causal research in education was almost strictly quantitative twenty years ago, however, that landscape has changed considerably. The number of intervention studies fielded and completed annually has increased substantially, and the quality of the evaluations is much more robust, including paying much greater attention…

It is a healthy exercise to debate the merits of using effect-size benchmarks to interpret research findings. However, these debates obscure a more central insight that emerges from empirical distributions of effect-size estimates in the literature: Efforts to improve education often fail to move the needle. I find that 36% of effect sizes from…

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,…

Evidence-based education aims to support policy makers choosing between potential interventions. This rarely involves considering each in isolation; instead, sets of evidence regarding many potential policy interventions are considered. Filtering a set on any quantity measured with error risks the "winner's curse": conditional on…

This paper seeks to raise awareness among educational researchers and practitioners of some significant weaknesses and internal contradictions of randomised control trials (RCTs). Although critiques throughout the years from education scholars have pointed to the detrimental effects of this experimental approach on education practice and values,…

In the 2016-2017 school year, the Liberian government launched Partnership Schools For Liberia (PSL), a pilot program in which the management of 93 primary schools was transferred to 8 private contractors. The pilot owed much to the importation of western policy models and was facilitated by the British organisation ARK and involved BIA, a private…

Within evidence-based education, results from randomised controlled trials (RCTs), and meta-analyses of them, are taken as reliable evidence for effectiveness -- they speak to "what works". Extending RCT results requires establishing that study samples and settings are representative of the intended target. Although widely recognised as…

This article addresses the gap between what works in research and what works in practice. Currently, research in evidence-based education policy and practice focuses on randomized controlled trials. These can support causal ascriptions ("It worked") but provide little basis for local effectiveness predictions ("It will work…

In the past few decades, we have seen a rapid proliferation in the use of quasi-experimental research designs in education research. This trend, stemming in part from the "credibility revolution" in the social sciences, particularly economics, is notable along with the increasing use of randomized controlled trials in the strive toward…

School-based evaluations of interventions are increasingly common in education research. Ideally, the results of these evaluations are used to make evidence-based policy decisions for students. However, it is difficult to make generalizations from these evaluations because the types of schools included in the studies are typically not selected…

The United States considers educating all students to a threshold of adequate outcomes to be a central goal of educational justice. The No Child Left Behind Act introduced evidence-based policy and accountability protocols to ensure that all students receive an education that enables them to meet adequacy standards. Unfortunately, evidence-based…

Policymakers, experts and advocates have promoted many different types of education reform over the past few decades, but what is the evidence about the efficacy of these programs? EdChoice partnered with Hanover Research to find out what research has been conducted in nine major education reform areas focusing on outcomes related to student…

Background: The Scandinavian countries have a long history of implementing social interventions, but the interventions have not been examined using randomised controlled trials until relatively recently compared with countries like the United States and the United Kingdom. Purpose: The purpose of this paper is to examine the history of randomised…

As a systemic approach to improving educational practice through research, "What Works" has come under repeated challenge from alternative approaches, most recently that of improvement science. While "What Works" remains a dominant paradigm for centralized knowledge-building efforts, there is need to understand why this…