On the Importance of Coefficient Alpha for Measurement Research: Loading Equality Is Not Necessary for Alpha's Utility as a Scale Reliability Index

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

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 arbitrarily small in any considered population and hence practically ignorable. In addition, the set of parameter values where this discrepancy is negligible is shown to possess the same dimensionality as that of the underlying model parameter space. The article contributes to the measurement and related literature by pointing out that (a) approximate or strict loading identity is not a necessary condition for the utility of alpha as a trustworthy index of scale reliability, and (b) coefficient alpha can be a dependable reliability measure with any extent of inequality in the component loadings.

Details

Original languageEnglish
Article number766 - 781
Pages (from-to)766-781
Number of pages16
JournalEducational and psychological measurement : EPM ; a bimonthly journal devoted to the development and application of measures of individual differences
Volume83
Issue number4
Early online dateJul 2022
Publication statusPublished - Aug 2023
Peer-reviewedYes

External IDs

Scopus 85134612144
ORCID /0000-0003-1106-474X/work/151436754
PubMed 37398845
Mendeley 49578ffb-db16-3b55-9686-664eb876d2bc

Keywords

Keywords

  • Coefficient alpha, Measurement, Multicomponent instrument, Parameter space, Population reliability to alpha discrepancy, Scale reliability, Single-factor model, Unidimensionality, coefficient alpha, measurement, multicomponent instrument, parameter space, population reliability to alpha discrepancy, scale reliability, single-factor model, unidimensionality