Network meta-analysis (NMA) incorporates all available evidence into a general statistical framework for comparing multiple treatments. Standard NMAs make three major assumptions, namely homogeneity, similarity, and consistency, and violating these assumptions threatens an NMA's validity. In this article, we suggest a graphical approach to…

Describing the variation in test scores between and within school districts is critical for: (1) for policy-related and descriptive work that investigates the sorting of students among districts and the differential effectiveness of those districts; and (2) for methodological work planning future experiments or interventions. Intraclass…

The purpose of this study is to study the performance of different methods (inverse probability weighting and estimation of informative bounds) to control for differential attrition by comparing the results of different methods using two datasets: an original dataset from Portland Public Schools (PPS) subject to high rates of differential…

Most quantitative analyses in workforce education are affected by missing data. Traditional approaches to remedy missing data problems often result in reduced statistical power and biased parameter estimates due to systematic differences between missing and observed values. This article examines the treatment of missing data in pertinent…

This study replicates and extends a 2004 content analysis of three major higher education journals. The original study examined the methodological characteristics of all published research in these journals from 1996 to 2000, recommending that higher education programs adjust their graduate training to better match the heavily quantitative and…

This brief considers the problem of using value-added scores to compare teachers who work in different schools. The author focuses on whether such comparisons can be regarded as fair, or, in statistical language, "unbiased." An unbiased measure does not systematically favor teachers because of the backgrounds of the students they are…

Little is known about levels of personal growth attributed by students to typical college life experiences. This paper documents two studies of student self-reported and posttraumatic growth and compares growth levels across populations. Both studies measure student attributions of cause to academic and non-academic experiences, respectively. It…

The capacity of Bayesian methods in estimating complex statistical models is undeniable. Bayesian data analysis is seen as having a range of advantages, such as an intuitive probabilistic interpretation of the parameters of interest, the efficient incorporation of prior information to empirical data analysis, model averaging and model selection.…

Adjustment methods such as propensity scores and analysis of covariance are often used for estimating treatment effects in nonexperimental data. Shadish, Clark, and Steiner used a within-study comparison to test how well these adjustments work in practice. They randomly assigned participating students to a randomized or nonrandomized experiment.…

This article reviews and discusses the use of statistical concepts in a natural resources and life sciences journal on the basis of a census of the articles published in a recent issue of the "Agronomy Journal" and presents a flow chart and a graph that display the inter-relationships between the most commonly used statistical terms. It also…

Three different nonparametric tests for scale--the Siegel-Tukey (S-T), the Mood (M), and the Normal Scores (NS)--are compared in order to contrast varying methods of scale test development and usage. Procedures for developing the three scale tests are discussed, and two examples of the use of each test in solving the same problem are given. From…

Accuracy was compared for three methods of implementing parallel analysis with mean eigenvalues (regression, interpolation, and computation with three samples of random data). The accuracy of parallel analysis with 95th percentile eigenvalues (through regression and interpolation) was also considered. No evidence of differential accuracy emerged…

Compared two types of empirical study with two types of conceptual research on the validity of the Rorschach. Argues that the Rorschach does have some validity and that poor research is at least partly culpable for the Rorschach's perceived failure. (Author/BL)

Twenty-three different methods of cluster analysis were compared in a four-stage sequential validation design. Results demonstrated that the solution given by Ward's method of cluster analysis was particularly powerful in comparison to solutions yielded by other techniques. (Author/JKS)

The all-possible subset approach is recommended as an alternative over stepwise methods for selecting the best set of predictor variables for multiple regression. Several criteria are available for selecting the best subset model. These are compared with the principal component regression (PCR) method to investigate their usefulness for subset…