During the past decade, the use of standardized benchmark measures to differentiate and individualize instruction for students received renewed attention from educators. Although teachers may use their own assessments (tests, quizzes, homework, problem sets) for monitoring learning, it is challenging for them to equate performance on classroom…

The present article provides a primer on using effect sizes in research. A small heuristic data set is used in order to make the discussion concrete. Additionally, various admonitions for best practice in reporting and interpreting effect sizes are presented. Among these is the admonition to not use Cohen's benchmarks for "small," "medium," and…

OKAim: The aim of this systematic review was to examine the literature on the effects of partial body-weight support treadmill training (PBWSTT) in children with cerebral palsy (CP) on functional outcomes and attainment of ambulation. Method: We searched the relevant literature from 1950 to July 2007. We found eight studies on the use of PWSBTT on…

The sense that replicability is an important aspect of empirical science led Killeen (2005a) to define "p[subscript rep]," the probability that a replication will result in an outcome in the same direction as that found in a current experiment. Since then, several authors have praised and criticized 'p[subscript rep]," culminating…

This comment offers three descriptions of "p[subscript rep]" that start with a frequentist account of confidence intervals, draw on R. A. Fisher's fiducial argument, and do not make Bayesian assumptions. Links are described among "p[subscript rep]," "p" values, and the probability a confidence interval will capture…

With its critical assessments of scientific evidence on the effectiveness of education programs, policies, and practices (referred to as "interventions"), and a range of products summarizing this evidence, the What Works Clearinghouse (WWC) is an important part of the Institute of Education Sciences' strategy to use rigorous and relevant…

In elementary books on applied statistics (e.g., Siegel, 1988; Agresti, 1990) and books on research methodology in psychology and personality assessment (e.g., Aiken, 1999), it is often suggested that the choice of a statistical test and the choice of statistical operations should be determined by the level of measurement of the data. Although…

REL Appalachia conducted a systematic review of the research evidence on the effects of increased learning time. After screening more than 7,000 studies, REL Appalachia identified 30 that met the most rigorous standards for research. A review of those 30 studies found that increased learning time does not always produce positive results. However,…

This NCEE Technical Methods report examines how to address the problem of missing data in the analysis of data in Randomized Controlled Trials (RCTs) of educational interventions, with a particular focus on the common educational situation in which groups of students such as entire classrooms or schools are randomized. Missing outcome data are a…

We consider the effects of daytime fasting by pregnant women during the lunar month of Ramadan on their children's test scores at age seven. Using English register data, we find that scores are 0.05 to 0.08 standard deviations lower for Pakistani and Bangladeshi students exposed to Ramadan in early pregnancy. These estimates are downward biased to…

Throughout history human subject research has been plagued by researchers whose studies were riddled with danger and/or risk to their subjects. Indeed, one may cite numerous situations where human subjects were injured and/or killed in experiments that were designed with no thought or anticipation of risk to the subjects. As a result, the federal…

Quality performance of the increasingly important professional role of the teacher requires a continued learning and professional growth of every individual. Action research represents one of the important factors in teachers' professional development, in particular when it is designed as a collaborative process involving teachers and researchers.…

This article reviews the literature on interventions targeting the academic performance of students with attention-deficit/hyperactivity disorder (ADHD) and does so within the context of the statistical significance testing controversy. Both the arguments for and against null hypothesis statistical significance tests are reviewed. Recent standards…

The recent American Psychological Association Task Force on Statistical Inference report suggested that confidence intervals should always be reported. Other researchers also agree that confidence intervals should be used as a supplement to statistical significance testing. The confidence interval is defined as a range of values constructed around…

This study investigated the extent that cooperative group members' levels of hopefulness, operationalized as a combination of pathways to meet desired goals and the agentic thinking that motivates an individual to use those pathways, predict (a) group performance, namely, the quality of an article critique assignment and research proposal…