Adjacent category logit models are ordered regression models that focus on comparisons of adjacent categories. These models are particularly useful for ordinal response variables with categories that are of substantive interest. In this article, we consider unconstrained and constrained versions of the partial adjacent category logit model, which…

Comparative interrupted time series (CITS) designs evaluate impact by modeling the relative deviation from trends among a treatment and comparison group after an intervention. The broad applicability of the design means it is widely used in education research. Like all non-experimental evaluation methods however, the internal validity of a given…

Meta-analysis of individual participant data (IPD) is considered the "gold-standard" for synthesizing clinical study evidence. However, gaining access to IPD can be a laborious task (if possible at all) and in practice only summary (aggregate) data are commonly available. In this work we focus on meta-analytic approaches of comparative…

Measurement invariance is a necessary precondition for meaningful cross-country comparisons, and three levels have been differentiated: configural, metric, and scalar. Unfortunately, establishing the most stringent form, that is, scalar measurement invariance, across groups is difficult. Recently, Muthén and Asparouhov proposed testing for…

Both the statistical and interpretational shortcomings of the three-parameter logistic (3PL) model in accommodating guessing effects on multiple-choice items are well documented. We consider the use of a residual heteroscedasticity (RH) model as an alternative, and compare its performance to the 3PL with real test data sets and through simulation…

Researchers are often interested in establishing equivalence of population variances. Traditional difference-based procedures are appropriate to answer questions about differences in some statistic (e.g., variances, etc.). However, if a researcher is interested in evaluating the equivalence of population variances, it is more appropriate to use a…

We conducted a systematic literature review of 111 empirical studies published between 1969 and 2018. We found that research does not exponentially grow in comparison to research on higher education or leadership; empirical research emerging in the 1980s does not completely replace non-empirical inquiry. Studies from English-speaking authors…

The purpose of the present study is to compare nonnormal distributions (i.e., t, skew-normal, skew-t with equal skew and skew-t with unequal skew) in growth mixture models (GMMs) based on diverse conditions of a number of time points, sample sizes, and skewness for intercepts. To carry out this research, two simulation studies were conducted with…

It is necessary to examine the measurement invariance (MI) among groups in studies where different groups are compared by using a measurement instrument. Most of the studies, measurement invariance is tested with multiple group confirmatory factor analysis. This model applies many model adjustments based on the modification indexes. Therefore, it…

In the context of examinations, the phrase "maintaining standards" usually refers to any activity designed to ensure that it is no easier (or harder) to achieve a given grade in one year than in another. Specifically, it tends to mean activities associated with setting examination grade boundaries. Benton et al (2020) describes a method…

Purpose: Agricultural extension services in poor countries often identify opinion leaders based on criteria such as wealth and social status. We explore the effectiveness of this top-down approach by analysing the role of so-called model and nodal farmers in the diffusion of malt barley in a highland community in Ethiopia. Research approach: We…

The aim of this investigation is to compare velocity and power variables during loaded-squat jump (SJ[subscript Loaded]) exercise of national athletes dealing with different sports branches and to identify whether velocity and power parameters become different or not according to branches. In accordance with this purpose, a total of 36 national…

We derive sample-allocation formulas that maximize the power of several mediation tests in two-level-group-randomized studies under a linear cost structure and fixed budget. The results suggest that the optimal individual sample size is typically smaller than that associated with the detection of a main effect and is frequently less than 10 under…

Purpose: Metabolic perturbation and VO[subscript 2] on-kinetics are potential modifiers of fatigue and vary in importance depending on the exercise task. Thus, performance fatigability during high-intensity exercise seems to be exercise mode dependent, affecting tolerance in the severe domain. However, the effects of exercise mode on severe domain…

For the two-way factorial design in analysis of variance, the current article explicates and compares three methods for controlling the Type I error rate for all possible simple interaction contrasts following a statistically significant interaction, including a proposed modification to the Bonferroni procedure that increases the power of…