Correcting coefficient alpha for correlated errors: Is alpha(K) a lower bound to reliability?

Gordon Rae

    Research output: Contribution to journalArticle

    7 Citations (Scopus)


    When errors of measurement are positively correlated, coefficient alpha may overestimate the ``true'' reliability of a composite. To reduce this inflation bias, Komaroff (1997) has proposed an adjusted alpha coefficient, alpha(K). This article shows that alpha(K) is only guaranteed to be a lower bound to reliability if the latter does not include correlated error. If one's definition of reliability includes correlated error, then an alternative adjusted alpha, alpha(R), is suggested, which will always be a lower bound.
    Original languageEnglish
    Pages (from-to)56-59
    JournalApplied Psychological Measurement
    Issue number1
    Publication statusPublished - Jan 2006


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