Students often believe that statistical significance is the only determinant of whether a quantitative result is "important." In this paper, I review traditional null hypothesis statistical testing to identify what questions inferential statistics can and cannot answer, including statistical significance, effect size and direction,…

In this study, we re-analyze recent empirical research on replication from a meta-analytic perspective. We argue that there are different ways to define "replication failure," and that analyses can focus on exploring variation among replication studies or assess whether their results contradict the findings of the original study. We…

In the field of special education there is a dearth of group experimental studies that establish evidence-based practice. The effort to establish evidence-based practice has been associated with emphasizing experiments by using randomized controlled trial with large numbers of participants who are randomly assigned to a treatment. However,…

The effective evaluation of correctional programs is critically important. However, research in corrections rarely allows for the randomization of offenders to conditions of the study. This limitation compromises internal validity, and thus, causal conclusions can rarely be drawn. Increasingly, researchers are employing propensity score matching…

Despite recent emphasis on the use of randomized control trials (RCTs) for evaluating education interventions, in most areas of education research, observational methods remain the dominant approach for assessing program effects. Over the last three decades, the within-study comparison (WSC) design has emerged as a method for evaluating the…

In a meta-analytic review of critical thinking in social work education, findings revealed variability in research designs, methods, and subsequent findings. The 10 studies reviewed assessed different components of critical thinking and highlighted different potential moderator variables. Although there are significant limitations to all the…

To date, evaluation research and policy analysis have focused mainly on average program impacts and paid little systematic attention to their variation. Recently, the growing number of multi-site randomized trials that are being planned and conducted make it increasingly feasible to study "cross-site" variation in impacts. Important…

The motivation for this paper is the authors' recent work on several randomized control trials in which they found the primary result, which averaged across subgroups or sites, to be moderated by demographic or site characteristics. They are led to examine a distinction that the Institute of Education Sciences (IES) makes between "confirmatory"…

To describe the recent practice of evaluation, specifically method and design choices, the authors performed a content analysis on 117 evaluation studies published in eight North American evaluation-focused journals for a 3-year period (2004-2006). The authors chose this time span because it follows the scientifically based research (SBR)…

The 2011 NAEP-TIMSS linking study conducted by the National Center for Education Statistics (NCES) was designed to predict Trends in International Mathematics and Science Study (TIMSS) scores for the U.S. states that participated in 2011 National Assessment of Educational Progress (NAEP) mathematics and science assessment of eighth-grade students.…

Previous research conducted by Nelson and Coorough (1994) found support for the statement that PhD programs were more research oriented, whereas doctorate of education (EdD) programs were more oriented to the educational practitioner. This previous study, however, had grouped all dissertations in education and had not looked at dissertations by…

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 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…

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…

Written by a social worker for social work students, this is a nuts and bolts guide to statistics that presents complex calculations and concepts in clear, easy-to-understand language. It includes numerous examples, data sets, and issues that students will encounter in social work practice. The first section introduces basic concepts and terms to…