Background: Power analyses for a cluster-randomized trial (CRT) require estimates of additional design parameters beyond those needed for an individually randomized trial. In a 2-level CRT, there are two sample sizes, the number of clusters and the number of individuals per cluster. The intraclass correlation (ICC), or the proportion of variance…

Cluster randomized trials (CRTs) are commonly used to evaluate the causal effects of educational interventions, where the entire clusters (e.g., schools) are randomly assigned to treatment or control conditions. This study introduces statistical methods for designing and analyzing two-level (e.g., students nested within schools) and three-level…

In education research, small samples are common because of financial limitations, logistical challenges, or exploratory studies. With small samples, statistical principles on which researchers rely do not hold, leading to trust issues with model estimates and possible replication issues when scaling up. Researchers are generally aware of such…

Although it is widely known that special assumptions are needed for univariate analysis of repeated measures data, researchers seldom examine their data for violation of these assumptions. This paper reviews ways in which repeated measures analyses are usually handled and describes limitations of these methods. A design with two within subject…

While the author and Raymond Cattell approach personality study differently, their similar conclusions reveal their constructs and theories as complimentary, not contradictory. They agree on major issues: the existence of general personality traits with consistent associated behaviors, the relevance of multivariate studies, and the importance of…

A method is presented for determining the optimal number of conditions to use in measurement designs when resource constraints are imposed. The method is illustrated using a multivariate two-facet design, and extensions to other designs are discussed. (SLD)

The author examined the prevalence of multiple operational definitions of outcome constructs and an estimate of the incidence of Type I error rates when univariate procedures were applied to multiple variables in educational psychology. Multiple operational definitions of constructs were advocated and wider use of multivariate analysis was…

Hypothetical data sets are used to demonstrate how canonical correlation methods subsume other commonly utilized parametric methods. Analysis of variance, analysis of covariance, multiple analysis of variance, and multiple analysis of covariance are heavily used by educational researchers. It is concluded that researchers would do well to consider…

Dissertations are an important component of the effort to generate knowledge. Thus, dissertation quality may be seen by accreditation and coordinating-board reviewers as a noteworthy reflection on the quality of doctoral programs themselves. The present study reviews methodological errors within Ph.D. dissertations. The illustrative errors are…