Omega over alpha for reliability estimation of unidimensional communication measures

Abstract

ABSTRACT Cronbach’s alpha (coefficient α) is the conventional statistic communication scholars use to estimate the reliability of multi-item measurement instruments. For many, if not most communication measures, α should not be calculated for reliability estimation. Instead, coefficient omega (ω) should be reported as it aligns with the definition of reliability itself. In this primer, we review α and ω, and explain why ω should be the new ‘gold standard’ in reliability estimation. Using Mplus, we demonstrate how ω is calculated on an available data set and show how preliminary scales can be revised with ‘ω if item deleted.’ We also list several easy-to-use resources to calculate ω in other software programs. Communication researchers should routinely report ω instead of α.