Likert-type item is the most popular response format for collecting data in social, educational, and psychological studies through scales or questionnaires. However, there is no consensus on whether parametric or non-parametric tests should be preferred when analyzing Likert-type data. This study examined the statistical power of parametric and…

Large-scale randomized studies provide the best means of evaluating practical, replicable approaches to improving educational outcomes. This article discusses the advantages, problems, and pitfalls of these evaluations, focusing on alternative methods of randomization, recruitment, ensuring high-quality implementation, dealing with attrition, and…

The purpose of this study is both to gather the experimental studies which investigate the effect of creative drama on the attitudes of students towards the courses and to synthesize the findings of these studies. The studies within the scope of this current research were obtained from various databases such as "ProQuest Citations, Council of…

Purpose: Instructional leadership has assumed steadily increasing importance within the general role set of principals over the past 60 years. One persisting finding within this corpus of studies concerns the consistently higher ratings obtained by female principals on instructional leadership when compared with their male counterparts. This…

With growing popularity of single subject design as a method to evaluate the efficacy of interventions, it is important to ensure that the analyses of these methods are rigorous and reliable. The purpose of this case study is to discuss the measures used to evaluate the efficacy of interventions in single subject design studies in the fields of…

Using data from the 2006 Program for International Student Assessment (PISA), we explored nine aspects of science engagement (science self-efficacy, science self-concept, enjoyment of science, general interest in learning science, instrumental motivation for science, future-oriented science motivation, general value of science, personal value of…

Researchers are strongly encouraged to accompany the results of statistical tests with appropriate estimates of effect size. For 2-group comparisons, a probability-based effect size estimator ("A") has many appealing properties (e.g., it is easy to understand, robust to violations of parametric assumptions, insensitive to outliers). We review…

In some instances, intentionally or not, study designs are such that there is clustering in one group but not in the other. This paper describes methods for computing effect size estimates and their variances when there is clustering in only one group and the analysis has not taken that clustering into account. The authors provide the effect size…

In this study, we examined the college-readiness rates of Black, Hispanic, and White Texas public high school graduates using archival data from the Texas Education Agency Academic Excellence Indicator System. An examination of the state college-readiness rates across a 3-year period was conducted to determine the extent to which academic…

This addendum to previously published results presents alternative analyses of data from large-scale effectiveness studies of Cognitive Tutor Algebra I in middle schools and high schools. These alternative analyses produce results that are substantively the same as previously reported. We find a significant positive effect of 0.21 standard…

We analyzed the effect of grade span configurations (i.e., 6-8 versus K-8) on reading and math performance in Texas public schools for the last 5 school years. Participants in this study were 628 Texas schools (i.e., 314 middle schools and 314 K-8 schools) distributed across the 5 school years examined. Schools configured as K-8 schools were…

This paper includes a nontechnical description of methods for calculating effect sizes in intellectual and developmental disability studies. Different hypothetical studies are used to illustrate how null hypothesis significance testing (NHST) and effect size findings can result in quite different outcomes and therefore conflicting results. Whereas…

Zimmerman, Christakis, and Meltzoff (2007) reported that exposure to Baby Einstein videos was negatively associated with language development. The current study uses the Zimmerman et al. (2007) data set to replicate and extend the original analyses. Caregivers of 392 children aged 6 to 16 months and 358 children aged 17 to 27 months reported on…

This "What Works Clearinghouse Procedures and Standards Handbook (Version 3.0)" provides a detailed description of the standards and procedures of the What Works Clearinghouse (WWC). The remaining chapters of this Handbook are organized to take the reader through the basic steps that the WWC uses to develop a review protocol, identify…

This study compared the accuracies of four differential item functioning (DIF) estimation methods, where each method makes use of only one of the following: raw data, logistic regression, loglinear models, or kernel smoothing. The major focus was on the estimation strategies' potential for estimating score-level, conditional DIF. A secondary focus…