Evaluators of education interventions are increasingly designing studies to detect impacts much smaller than the 0.20 standard deviations that Cohen characterized as "small." While the need to detect smaller impacts is based on compelling arguments that such impacts are substantively meaningful, the drive to detect smaller impacts may…

The use of singular methodologies has dominated emotional and behavioral disorder (EBD) intervention research, and by extension, the field has not deployed mixed-methods research (MMR). The purpose of this article is to provide an overview of MMR and demonstrate its utility for conducting EBD intervention research. The basic tenants and design…

Evaluators of education interventions increasingly need to design studies to detect impacts much smaller than the 0.20 standard deviations that Cohen (1988) characterized as "small." For example, an evaluation of Response to Intervention from the Institute of Education Sciences (IES) detected impacts ranging from 0.13 to 0.17 standard…

Respondent incentives are widely used to increase response rates, but their effect on nonresponse bias has not been researched as much. To contribute to the research, we analyze an incentive experiment embedded within the third wave of the German household panel survey "Panel Labor Market and Social Security" conducted by the German…

Evaluators of education interventions are increasingly designing studies to detect impacts much smaller than the 0.20 standard deviations that Cohen (1988) characterized as "small." While the need to detect smaller impacts is based on compelling arguments that such impacts are substantively meaningful, the drive to detect smaller impacts…

In a randomized controlled trial, a decision needs to be made about the total number of subjects for adequate statistical power. One way to increase the power of a trial is by including a predictive covariate in the model. In this article, the effects of various covariate adjustment strategies on increasing the power is studied for discrete-time…

Childhood obesity is one of the most serious challenges of the 21st century and it is vital that evidence-based treatment approaches can be translated into practice to meet public health needs. Yet policy-makers cannot afford to wait for the results of lengthy trials before "probably efficacious" interventions are made available to the public, and…

Attrition occurs when study participants who were assigned to the treatment and control conditions do not provide outcome data and thus do not contribute to the estimation of the treatment effects. It is very common in experimental studies in education as illustrated, for instance, in a meta-analysis studying "the effects of attrition on baseline…

As teacher professional development research includes more experimental designs, new challenges arise. We examine the threat of participant attrition as an example of the types of problems researchers face. Counter-intuitively, higher levels of recruitment effort were related to higher dropout rates among teachers. We also found that teachers left…

Drawing on our five years of experience developing WWC evidence standards and reviewing studies against those standards as well as current literature on the design of impact studies, we highlight in this paper some of the most critical issues and common pitfalls in designing and conducting impact studies in education, and provide practical…

E-learning researchers face considerable challenges in creating meaningful and generalizable studies due to the complex nature of this dynamic training medium. Our experience in conducting workplace e-learning research led us to create this guide for planning research on e-learning. We share the unanticipated complications we encountered in our…

This paper introduces a variation on the post-test only cohort control design and addresses questions concerning both the methodological credibility and the practical utility of employing this design variation in evaluations of large-scale complex professional development programmes in mathematics education. The original design and design…

This monograph looks first at opportunities provided by research in the adult literacy field and then identifies challenges to scientific research and suggests ways to address these challenges so that better evidence can be generated in the future. It has two goals that support the building of a stronger research base for the adult literacy…

Active parental consent policies have been blamed for low participation rates and selection bias (i.e., loss of "high-risk" youths) in school-based studies. In this article, the authors describe active consent procedures that produced an overall active consent rate of 79% in a sample of more than 4,500 middle school students attending 29…

Although time and resource intensive, longitudinal studies offer the ability to examine the direction and magnitude of causal relationships that cannot be accomplished through cross-sectional design. (Contains 1 figure.)