Pearson's correlation is widely used to test for an association between two variables and also forms the basis of several multivariate statistical procedures including many latent variable models. Spearman's [rho] is a popular alternative. These procedures are compared with ranking the data and then applying the inverse normal transformation, or…

Parallel analysis has been considered one of the most accurate methods for determining the number of factors in factor analysis. One major advantage of parallel analysis over traditional factor retention methods (e.g., Kaiser's rule) is that it addresses the sampling variability of eigenvalues obtained from the identity matrix, representing the…

Cluster-randomized trials have been widely used to evaluate the treatment effects of interventions on student outcomes. When interventions are implemented by teachers, researchers need to account for the nested structure in schools (i.e., students are nested within teachers nested within schools). Schools usually have a very limited number of…

Determining the number of factors in exploratory factor analysis is arguably the most crucial decision a researcher faces when conducting the analysis. While several simulation studies exist that compare various so-called factor retention criteria under different data conditions, little is known about the impact of missing data on this process.…

A new index of item discrimination power (IDP), dimension-corrected Somers' D (D2) is proposed. Somers' D is one of the superior alternatives for item-total- (Rit) and item-rest correlation (Rir) in reflecting the real IDP with items with scales 0/1 and 0/1/2, that is, up to three categories. D also reaches the extreme value +1 and -1 correctly…

Background: Researchers are often interested in testing the effectiveness of an intervention on multiple outcomes, for multiple subgroups, at multiple points in time, or across multiple treatment groups. The resulting multiplicity of statistical hypothesis tests can lead to spurious findings of effects. Multiple testing procedures (MTPs)…

Purpose: This study used a computational vocal tract model to investigate the relationship of diphthong duration and vocal tract movement magnitude to measures of the F2 trajectory in CV words. Method: Three words ("bough," "boy," and "buy") were simulated on the basis of an adult female vocal tract model, in which…

Utilizing a longitudinal item response model, this study investigated the effect of item parameter drift (IPD) on item parameters and person scores via a Monte Carlo study. Item parameter recovery was investigated for various IPD patterns in terms of bias and root mean-square error (RMSE), and percentage of time the 95% confidence interval covered…

With a view to enhancing the entrepreneurial activity of universities, the authors explore the concepts and features of the "experimental lab", presenting it as an effective means of supporting entrepreneurial training programmes and helping students to turn ideas into actual start-ups. In this context, the term experimental lab refers…

Since researchers investigated automatic scoring systems in writing assessments, they have dealt with relationships between human and machine scoring, and then have suggested evaluation criteria for inter-rater agreement. The main purpose of my study is to investigate the magnitudes of and relationships among indices for inter-rater agreement used…

An aggregation strategy is proposed to potentially address practical limitation related to computing resources for two-level multidimensional item response theory (MIRT) models with large data sets. The aggregate model is derived by integration of the normal ogive model, and an adaptation of the stochastic approximation expectation maximization…

Within the teaching of political theory, an assumption is emerging that "Reacting to the Past" simulations are an effective tool because they encourage greater student engagement with ideas and history. While previous studies have assessed the advantages of simulations in other political science subfields or offered anecdotal evidence of…

Background: Simulation can produce highly qualified professionals, however, it can also be perceived as stressful and frustrating by the nursing students. Purposes: This study was to identify the attitudes and perceptions of Jordanian nursing students toward simulation as an educational strategy, to investigate whether certain students'…

The detection of complexity in behavioral outcomes often requires an estimation of their variability over a prolonged time spectrum to assess processes of stability and transformation. Conventional scholarship typically relies on time-independent measures, "snapshots", to analyze those outcomes, assuming that group means and their…

The magnitude of symptom inter-correlations in diagnosed individuals has contributed to the evidence that autism spectrum disorders (ASD) is a fractionable disorder. Such correlations may substantially under-estimate the population correlations among symptoms due to simultaneous selection on the areas of deficit required for diagnosis. Using…