Item-Score Reliability in Empirical-Data Sets and Its Relationship With Other Item Indices. (December 2018)

• Record Type: Journal Article
• Authors: Zijlmans, Eva A. O.; Tijmstra, Jesper; van der Ark, L. Andries; Sijtsma, Klaas
• Is Part Of: Educational and psychological measurement. Volume 78:Number 6(2018)
• Page Start: 998
• Page End: 1020
• Publication Date: 2018-12
• Subjects: Coefficient λ6 -- correction for attenuation -- item discrimination -- item-factor loading -- item-rest correlation -- item scalability -- item-score reliability; Educational tests and measurements -- Periodicals; Psychological tests -- Periodicals; 151.205
• DOI: 10.1177/0013164417728358
• Languages: English
• ISSNs: 0013-1644

Abstract

Reliability is usually estimated for a total score, but it can also be estimated for item scores. Item-score reliability can be useful to assess the repeatability of an individual item score in a group. Three methods to estimate item-score reliability are discussed, known as method MS, methodλ 6, and method CA. The item-score reliability methods are compared with four well-known and widely accepted item indices, which are the item-rest correlation, the item-factor loading, the item scalability, and the item discrimination. Realistic values for item-score reliability in empirical-data sets are monitored to obtain an impression of the values to be expected in other empirical-data sets. The relation between the three item-score reliability methods and the four well-known item indices are investigated. Tentatively, a minimum value for the item-score reliability methods to be used in item analysis is recommended.