Traditional estimators of reliability such as coefficients alpha, theta, omega, and rho (maximal reliability) are prone to give radical underestimates of reliability for the tests common when testing educational achievement. These tests are often structured by widely deviating item difficulties. This is a typical pattern where the traditional…

Coefficient alpha reliability persists as the most common reliability coefficient reported in research. The assumptions for its use are, however, not well-understood. The current paper challenges the commonly used expressions of coefficient alpha and argues that while these expressions are correct when estimating reliability for summed scores,…

Questionnaire scales that are mixed-worded, i.e. include both positively and negatively worded items, often suffer from issues like low reliability and more complex latent structures than intended. Part of the problem might be that some responders fail to respond consistently to the mixed-worded items. We investigated the prevalence and impact of…

This study aimed to examine the effects of reverse items created with different strategies on psychometric properties and respondents' scale scores. To this end, three versions of a 10-item scale in the research were developed: 10 positive items were integrated in the first form (Form-P) and five positive and five reverse items in the other two…

This study presents a modified version of the Korean Elicited Imitation (EI) test, designed to resemble natural spoken language, and validates its reliability as a measure of proficiency. The study assesses the correlation between average test scores and Test of Proficiency in Korean (TOPIK) levels, examining score distributions among beginner,…

The reliability of a test score is usually underestimated and the deflation may be profound, 0.40 - 0.60 units of reliability or 46 - 71%. Eight root sources of the deflation are discussed and quantified by a simulation with 1,440 real-world datasets: (1) errors in the measurement modelling, (2) inefficiency in the estimator of reliability within…

The purpose of this article is to document the development of a new measure of teaching self-efficacy -- "The College Teaching Self-Efficacy (CTSE) Scale." We designed the CTSE scale to examine individuals' beliefs in their abilities to perform specific teaching tasks in a college classroom successfully. We developed an instrument that…

Many undergraduate chemistry students hold alternate conceptions related to resonance--an important and fundamental topic of organic chemistry. To help address these alternate conceptions, an organic chemistry instructor could administer the resonance concept inventory (RCI), which is a multiple-choice assessment that was designed to identify…

The paper proposes new measures of difficulty and discriminating values of binary items and test consisting of such items and find their relationships including estimation of test error variance and thereby the test reliability, as per definition using cosine similarities. The measures use entire data. Difficulty value of test and item is defined…

Estimation of parameters for the many-facets Rasch model requires that conditional on the values of the facets, such as person ability, item difficulty, and rater severity, the observed responses within each facet are independent. This requirement has often been discussed for the Rasch models and 2PL and 3PL models, but it becomes more complex…

It is imperative to collect validity evidence prior to interpreting and using test scores. During the process of collecting validity evidence, test developers should consider whether test scores are contaminated by sources of extraneous information. This is referred to as construct irrelevant variance, or the "degree to which test scores are…

The purpose of this study was to estimate the overall reliability values for the scores produced by Runco Ideational Behavior Scale (RIBS) and explore the variability of RIBS score reliability across studies. To achieve this, a reliability generalization meta-analysis was carried out using the 86 Cronbach's alpha estimates obtained from 77 studies…

This study aimed to develop a useful test to measure university students' spatial abilities validly and reliably. Following a sequential explanatory mixed methods research design, first, qualitative methods were used to develop the trial items for the test; next, the psychometric properties of the test were analyzed through quantitative methods…

Clinical, medical, and health psychologists use difference scores obtained from pretest--posttest designs employing the same test to assess intraindividual change possibly caused by an intervention addressing, for example, anxiety, depression, eating disorder, or addiction. Reliability of difference scores is important for interpreting observed…

This article extends multivariate generalizability theory (MGT) to tests with different random-effects designs for each level of a fixed facet. There are numerous situations in which the design of a test and the resulting data structure are not definable by a single design. One example is mixed-format tests that are composed of multiple-choice and…