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…

Pregnancy is a frequently applied exclusion criteria for many forms of research. Common justifications for this exclusion include the potential for teratogenicity, as well as the potential for physiologic changes in pregnancy to impact the research itself. The systematic exclusion of pregnant persons from clinical studies has created a significant…

Whether selection processes contribute to group-level disparities or merely reflect pre-existing inequalities is an important societal question. In the context of observational data, researchers, concerned about omitted-variable bias, assess selection-contributing inequality via a kitchen-sink approach, comparing selection outcomes of…

In educational contexts, students often self-select into specific interventions (e.g., courses, majors, extracurricular programming). When students self-select into an intervention, systematic group differences may impact the validity of inferences made regarding the effect of the intervention. Propensity score methods are commonly used to reduce…

A broad consensus exists that the use of appropriate methods are important in the Scholarship of Teaching and Learning. However, methodological controversies arise around what constitutes acceptable evidence, if one needs a control group, how generalizable results must be, and other similar issues. Much SoTL work, I argue, asks questions about how…

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…

An aspect of a study is considered a confounding factor if it is not possible to tell whether the difference in outcomes is due to the intervention, the confounding factor, or both. In What Works Clearinghouse (WWC) study reviews, certified reviewers look for a specific type of confounding factor: those that occur when a component of the study…

By creating and analyzing matched samples, researchers can simplify their analyses to include fewer covariate variables, relying less on model assumptions, and thus generating results that may be easier to report and interpret. When two groups essentially "look" the same, it is easier to explore their differences and make comparisons…

The What Works Clearinghouse (WWC) uses the term "baseline equivalence" when determining if the intervention group (those that received the intervention of interest) and the comparison group (those that did not receive the intervention) had characteristics that were similar enough ("equivalent") at the start of the study (at…

This article examines the scientific problem of the formation of professional competence of legal specialty students in the elective courses studying. The analysis has been conducted and the content of professional competence of legal specialty students has been substantiated. This work substantiates the role of elective courses in the formation…

"Attrition" is the loss of sample during the course of a study. It occurs when individuals initially randomly assigned in a study are not included when researchers examine the outcome of interest. Attrition is a common issue in education research, and it occurs for many reasons. The What Works Clearinghouse (WWC) is an initiative of the…

Purpose: To date, no studies have imaged the velopharynx in children with 22q11.2 deletion syndrome (22q11.2 DS) without the use of sedation. Dysmorphology in velopharyngeal structures has been shown to have significant negative implications on speech among these individuals. This single case study was designed to assess the feasibility of a…

Demonstration of experimental control is considered a hallmark of high-quality single-case research design (SCRD). Studies that fail to demonstrate experimental control may not be published because researchers are unwilling to submit these papers for publication and journals are unlikely to publish negative results (i.e., the file drawer effect).…

Rigorous scholarship is essential to the continued growth of group work, yet the unique nature of this counseling specialty poses challenges for quantitative researchers. The purpose of this proposal is to overview unique challenges to quantitative research with groups in the counseling field, including difficulty in obtaining large sample sizes…

Objective: There is substantial evidence that poorly designed and reported research can mislead decision making in clinical care. This review investigates the methodological quality of Swedish trials of a wide array of psychological and social interventions. Method: The review includes 302 articles published in peer-reviewed journals during…