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…

This study examined bias reduction in the eight nonequivalent comparison group designs (NECGDs) that result from combining (a) choice of a local versus non-local comparison group, and analytic use or not of (b) a pretest measure of the study outcome and (c) a rich set of other covariates. Bias was estimated as the difference in causal estimate…

To date, there has been mounting research evidence on the impact of written corrective feedback. In response to this, reviews have been conducted to condense either findings or methodologies through the combined analysis of EFL and ESL studies. Although syntheses shed light on the topic, no one provides exclusive insights into EFL realities.…

This integrative literature review takes up the ongoing discussion about the place of mixed methods designs in educational research. We focus on studies that investigate the role of argumentation in inquiry-based learning, either as a means for enhancing inquiry (argument-based inquiry) or as a learning outcome (inquiry-based argument). We argue…

To plan cluster-randomized trials with sufficient statistical power to detect intervention effects on student achievement, researchers need multilevel design parameters, including measures of between-classroom and between-school differences and the amounts of variance explained by covariates at the student, classroom, and school level. Previous…

Experimental research in education and training programs typically involves administering treatment to whole groups of individuals. As such, researchers rely on the estimation of design parameter values to conduct power analyses to efficiently plan their studies to detect desired effects. In this study, we present design parameter estimates from a…

An appropriate estimate of statistical power is critical for the design of intervention studies. Although the inclusion of a pretest covariate in the test of the primary outcome can increase statistical power, samples selected on the basis of pretest performance may demonstrate range restriction on the selection measure and other correlated…

In experimental research, internal validity refers to what extent researchers can conclude that changes in dependent variable (i.e. outcome) are caused by manipulations in independent variable. The causal inference permits researchers to meaningfully interpret research results. This article discusses (a) internal validity threats in social and…

E-learning research is plenty of difficulties, as also research in education is. Usually, the high number of features involved in e-learning processes complicates and masks the identification and isolation of the factors which cause the expected benefits, when they exist. At the same time, a bunch of threats are ready to weaken the validity of the…

This article reports on a design-based methodology of a thesis in which a fully face-to-face contact module was converted into a blended learning course. The purpose of the article is to report on how design-based phases, in the form of micro-, meso- and macro-cycles were applied to improve practice and to generate design principles. Design-based…

The purpose of this study was to compare the results of a regression discontinuity design (RDD) with those of an experimental design of a tiered vocabulary intervention for children at risk for reading disability to determine RDD's feasibility as a research methodology for this type of study. Researchers reanalyzed an archival dataset of a…

The purpose of this study was to examine the effects of Play Practice (PP) instruction on the performance of table tennis skills. Fifty-six college students in four intact classes were taught by two instructors using PP and Skill-focused Instruction (SI). A nonequivalent control/comparison group experimental design with pre and post measures was…

The regression discontinuity design (RDD) has the potential to yield findings with causal validity approaching that of the randomized controlled trial (RCT). However, Schochet (2008a) estimated that, on average, an RDD study of an education intervention would need to include three to four times as many schools or students as an RCT to produce…

This report describes a cluster randomized control trial (RCT) intervention study of the effectiveness of the ABRACADABRA (ABRA) Web-based literacy system using a classroom-level RCT intervention with 1,067 children in 74 kindergarten and Grade 1 or Grade 1/2 classrooms across Canada. The authors closely followed the CONSORT criteria for executing…

This article provides two illustrations of some of the factors that can influence findings from pre- and post-test research designs in evaluation studies, including regression to the mean (RTM), maturation, history and test effects. The first illustration involves a re-analysis of data from a study by Marsden (2004), in which pre-test scores are…