The purpose of this study was to investigate a new way of evaluating interrater reliability that can allow one to determine if two raters differ with respect to their rating on a polytomous rating scale or constructed response item. Specifically, differential item functioning (DIF) analyses were used to assess interrater reliability and compared…

The population relationship between coefficient alpha and scale reliability is studied in the widely used setting of unidimensional multicomponent measuring instruments. It is demonstrated that for any set of component loadings on the common factor, regardless of the extent of their inequality, the discrepancy between alpha and reliability can be…

Simulations concerning the distributional assumptions of coefficient alpha are contradictory. To provide a more principled theoretical framework, this article relies on the Fréchet-Hoeffding bounds, in order to showcase that the distribution of the items play a role on the estimation of correlations and covariances. More specifically, these bounds…

Among all, Cronbach's Alpha and McDonald's Omega are commonly used for reliability estimations. The alpha uses inter-item correlations while omega is based on a factor analysis result. This study uses simulated ordinal data sets to test whether the alpha and omega produce different estimates. Their performances were compared according to the…

Pearson product-moment correlation coefficient between item g and test score X, known as item-test or item-total correlation ("Rit"), and item-rest correlation ("Rir") are two of the most used classical estimators for item discrimination power (IDP). Both "Rit" and "Rir" underestimate IDP caused by the…

Objective: Various statistical methods have been developed to estimate hazard ratios (HRs) from published Kaplan-Meier (KM) curves for the purpose of performing meta-analyses. The objective of this study was to determine the reliability, accuracy, and precision of four commonly used methods by Guyot, Williamson, Parmar, and Hoyle and Henley.…

We examined the performance of coefficient alpha and its potential competitors (ordinal alpha, omega total, Revelle's omega total [omega RT], omega hierarchical [omega h], greatest lower bound [GLB], and coefficient "H") with continuous and discrete data having different types of non-normality. Results showed the estimation bias was…

Supervisors evaluated counselors-in-training at multiple points during their practicum experience using the Counseling Competencies Scale (CCS; N = 1,070). The CCS evaluations were randomly split to conduct exploratory factor analysis and confirmatory factor analysis, resulting in a 2-factor model (61.5% of the variance explained).

In The Netherlands, the 4-Skills Scan is an instrument for physical education teachers to assess gross motor skills of elementary school children. Little is known about its reliability. Therefore, in this study the test-retest and inter-rater reliability was determined. Respectively, 624 and 557 Dutch 6- to 12-year-old children were analyzed for…

To examine the reproducibility of three measurement techniques used to determine creatine kinase, interleukin-6 and high-sensitivity C-reactive protein, 50 participants had blood samples taken on two occasions. Fingertip plasma samples were analysed using the Reflotron for CK determination. Venous blood samples collected into serum separator tubes…

The purpose of this article was two-fold (1) provide an overview of the commonly reported and under-reported absolute agreement indices in the kinesiology literature for continuous data; and (2) present examples of these indices for hypothetical data along with recommendations for future use. It is recommended that three types of information be…

This article explores ways to assess interactional performance, and reports on the use of a test format that standardizes the interlocutor's linguistic and interactional contributions to the exchange. It describes the construction and administration of six scripted speech tasks (instruction, advice, and sales tasks) with pre-vocational learners (n…

This study aimed to compare between the students' self-assessment and teachers' assessment. The study sample consisted of 71 students at Tafila Technical University studying Introduction to Psychology course. The researcher used 2 students' self-assessment tools and 2 tests. The results indicated that students can assess themselves accurately if…

Data derived from universal screening procedures are increasingly utilized by schools to identify and provide additional support to students at risk for behavioral and emotional concerns. As screening has the potential to be resource intensive, effort has been placed on the development of efficient screening procedures, including brief behavior…

Much of the science reported in the media depends on correlation coefficients. But the size of correlation coefficients depends, in part, on the reliability with which the correlated variables are measured. Understanding this is a statistical literacy issue.