Until now, the conventional approach using two distinct groups, experimental and control, continues to dominate research, especially education research. Researchers, particularly those who are active in this domain, readily recognise this pattern when surveying literature. This article explores the use of the Solomon four-group design as a…

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…

Medical students must understand statistical reasoning and sample size selection to design and interpret clinical trials. Beyond achieving sufficient statistical power, ensuring meaningful precision in treatment effect estimates is equally important. We developed free, interactive Shiny/R tools that let learners explore how varying sample sizes…

Several branches of the potential outcome causal inference literature have discussed the merits of blocking versus complete randomization. Some have concluded it can never hurt the precision of estimates, and some have concluded it can hurt. In this article, we reconcile these apparently conflicting views, give a more thorough discussion of what…

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…

Group design studies in education include groups such as students, teachers, caregivers, schools, or districts assigned to conditions, typically treatment and control, to compare outcomes between the groups. Although the use of group designs in education has become more frequent and robust, the use of group designs in rural education lags far…

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…

Background/Context: Observational studies often employ regression discontinuity (RD) designs and multiple control-group designs to explore the causal quantities of interest. RD designs assess policy and program effectiveness by assigning subjects to treatment based on whether they exceed a pre-defined cutoff. RD designs are classified into two…

Background/Context: Some observational studies involve multiple layers of treatment selection, specifically in the context of the extended time accommodation (ETA) for English language learners (ELLs). In ETA settings, the first selection occurs due to the eligibility rule, where students whose ELL English proficiency is below a certain threshold…

Randomization of large number of participants to different treatment groups is often not a feasible or preferable way to answer questions of immediate interest to professional practice. Single case designs (SCDs) are a class of research designs that are experimental in nature but require only a few participants, all of whom receive the…

The purpose of this study is to examine whether the Grid Model practices affect students' motivation for self-regulation. In the study, quasi-experimental research design with pre-test/post-test control group was used. This study was conducted with a total of 74 students from 4th grade students in different primary schools in Amasya. Motivated…

The present study employed a quasi-experimental design to assess a computer-based tool, which was intended to scaffold the task of designing experiments when using a virtual lab for the process of experimentation. In particular, we assessed the impact of this tool on primary school students' cognitive processes and inquiry skills before and after…

Purpose: Among the gold standards in human resource development (HRD) research are studies that test theoretically developed hypotheses and use experimental designs. A somewhat typical experimental design would involve collecting pretest and posttest data on individuals assigned to a control or experimental group. Data from such a design that…

Improving academic, behavioural, and social outcomes of students through empirical research has been a firm commitment among researchers, policy-makers, and other professionals in education across Europe and the United States (U.S.). To assist in building scientific evidences, executive bodies such as the European Commission and the Institute for…

Purpose: Howard Gardners' concept of multiple intelligence (MI) offers an alternative perspective on intelligence which highlights the importance of acknowledging learner diversity, individual talents and the development of human potentials. MI has been used as a basis for the construction of modular enrichment activities to facilitate the…