Correcting Internal Consistency Estimates Inflated by Correlated Item Errors

Paola Pascual-Ferrá, Michael Beatty

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Coefficient alpha is perhaps the most widely employed estimate of reliability for self-report measures in communication research. However, coefficient alpha misestimates internal consistency when measures are not congeneric. Congeneric measures meet the assumption of classical test theory in that all item errors are uncorrelated or random; when item errors are correlated, the measure fails to be congeneric, signaling the presence of latent factor(s) other than those the researcher intended to measure. Scholars have alerted to the fact that many self-report measures used are noncongeneric and that coefficient alpha might be yielding inaccurate, often inflated, reliability estimates. In this essay, we propose a formula for estimating the internal consistency of a measure that reflects the degree to which reliability is affected by correlated item errors.

Original languageEnglish (US)
Pages (from-to)347-352
Number of pages6
JournalCommunication Research Reports
Volume32
Issue number4
DOIs
StatePublished - Oct 2 2015

Keywords

  • Coefficient Alpha
  • Congenericity
  • Correlated Item Errors
  • Measurement Error
  • Reliability

ASJC Scopus subject areas

  • Communication

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