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From alpha to omega: A practical solution to the pervasive problem of internal consistency estimation
Author(s) -
Dunn Thomas J.,
Baguley Thom,
Brunsden Vivienne
Publication year - 2014
Publication title -
british journal of psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.536
H-Index - 92
eISSN - 2044-8295
pISSN - 0007-1269
DOI - 10.1111/bjop.12046
Subject(s) - omega , alpha (finance) , psychology , internal consistency , reliability (semiconductor) , consistency (knowledge bases) , measure (data warehouse) , point (geometry) , statistics , cronbach's alpha , psychometrics , social psychology , clinical psychology , computer science , mathematics , artificial intelligence , data mining , physics , power (physics) , geometry , quantum mechanics
Coefficient alpha is the most popular measure of reliability (and certainly of internal consistency reliability) reported in psychological research. This is noteworthy given the numerous deficiencies of coefficient alpha documented in the psychometric literature. This mismatch between theory and practice appears to arise partly because users of psychological scales are unfamiliar with the psychometric literature on coefficient alpha and partly because alternatives to alpha are not widely known. We present a brief review of the psychometric literature on coefficient alpha, followed by a practical alternative in the form of coefficient omega. To facilitate the shift from alpha to omega, we also present a brief guide to the calculation of point and interval estimates of omega using a free, open source software environment.