This article reviews the origins and use of the terms quasi-experiment and natural experiment. It demonstrates how the terms conflate whether variation in the independent variable of interest falls short of random with whether researchers find, rather than intervene to create, that variation. Using the lens of assignment--the process driving…

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.…

By design, randomized experiments (XPs) rule out bias from confounded selection of participants into conditions. Quasi-experiments (QEs) are often considered second-best because they do not share this benefit. However, when results from XPs are used to generalize causal impacts, the benefit from unconfounded selection into conditions may be offset…

We consider situations in which public charter school lotteries are neither universally conducted nor consistently documented. Such lotteries produce "broken" Randomized Control Trials, but provide opportunities to assess the internal validity of quasi-experimental research designs. Here, we present the results of a statewide charter…

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…

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…

Background: Current policy discourses emphasise the importance of evidence in education, including evidencing the impact of teacher professional learning on student outcomes. Randomised controlled trial (RCT) designs are promoted to measure 'impact'. Recent debates about this reflect longer standing methodological disputes. Advocates of…

Randomized controlled trials (RCTs) and quasi-experimental designs like regression discontinuity (RD) designs, instrumental variable (IV) designs, and matching and propensity score (PS) designs are frequently used for inferring causal effects. It is well known that the features of these designs facilitate the identification of a causal estimand…

The central purpose of this article is to provide an overview of the many ways in which special educators can generate and think about causal inference to inform policy and practice. Consideration of causality across different lenses can be carried out by engaging in multiple method and mixed methods ways of thinking about inference. This article…

Objective: School refusal is a psychosocial problem associated with adverse short- and long-term consequences for children and adolescents. The authors conducted a systematic review and meta-analysis to examine the effects of psychosocial treatments for children and adolescents with school refusal. Method: A comprehensive search process was used…

Purpose: We conducted a retroactive analysis of teacher and student data from two randomized group trials and one well-controlled quasi-experimental group trial focused on improving pedagogical content knowledge (PCK) and student performance. Method: Seven teachers and 32 classes were investigated. PCK was measured using four variables: task…

Social cognitive theory (SCT) is a well-known theory for designing nutrition education and physical activity programs for adolescents. This systematic review aimed to evaluate the efficacy of intervention studies based on SCT in reducing or preventing overweight and obesity in adolescents. An electronic literature search in PubMed-Medline, Web of…

Background: Quasi-randomization might expedite recruitment into trials in emergency care settings but may also introduce selection bias. Methods: We searched the Cochrane Library and other databases for systematic reviews of interventions in emergency medicine or urgent care settings. We assessed selection bias (baseline imbalances) in prognostic…

Children with a diagnosis of autism are more likely to experience anxiety than their typically developing peers. Research suggests that Cognitive Behavioural Therapy (CBT) could offer a way to help children with autism manage their anxiety but most evidence is based on clinical trials. This study investigated a school-based CBT programme using a…

Persons with mental illness smoke at rates two to four times higher than do persons without mental illness and comprise 30.9% of the U.S. tobacco market. Given the prevalence of mental illness and the known detrimental effects of tobacco, concerted efforts are needed to promote the use of evidence-based treatment options. We conducted a systematic…