We discuss an application of Bayesian factor analysis for estimation of the optimal linear combination and associated maximal reliability of a multi-component measuring instrument. The described procedure yields point and credibility interval estimates of this reliability coefficient, which are readily obtained in educational and behavioral…

We compared coefficient alpha with five alternatives (omega total, omega RT, omega h, GLB, and coefficient H) in two simulation studies. Results showed for unidimensional scales, (a) all indices except omega h performed similarly well for most conditions; (b) alpha is still good; (c) GLB and coefficient H overestimated reliability with small…

Intensive longitudinal data is increasingly used to study state-like processes such as changes in daily stress. Measures aimed at collecting such data require the same level of scrutiny regarding scale reliability as traditional questionnaires. The most prevalent methods used to assess reliability of intensive longitudinal measures are based on…

KR-21 reliability and its extension (coefficient [alpha]) gives the reliability estimate of test scores under the assumption of tau-equivalent forms. KR-21 reliability gives the reliability estimate for summed scores for dichotomous items when items are randomly sampled from an infinite pool of similar items (randomly parallel forms). The article…

As the use of diagnostic assessment systems transitions from research applications to large-scale assessments for accountability purposes, reliability methods that provide evidence at each level of reporting are needed. The purpose of this paper is to summarize one simulation-based method for estimating and reporting reliability for an…

The answer-until-correct (AUC) method of multiple-choice (MC) testing involves test respondents making selections until the keyed answer is identified. Despite attendant benefits that include improved learning, broad student adoption, and facile administration of partial credit, the use of AUC methods for classroom testing has been extremely…

In multiple-choice tests, the quality of distractors may be more important than their number. We therefore examined the joint influence of distractor quality and quantity on test functioning by providing a sample of 5,793 participants with five parallel test sets consisting of items that differed in the number and quality of distractors.…