Use Omega Rather than Cronbach’s Alpha for Estimating Reliability. But…

Cronbach’s alpha (α) is a widely-used measure of reliability used to quantify the amount of random measurement error that exists in a sum score or average generated by a multi-item measurement scale. Yet methodologists have warned that α is not an optimal measure of reliability relative to its more general form, McDonald’s omega (ω). Among other reasons, that the computation of ω is not available as an option in many popular statistics programs and requires items loadings from a confirmatory factor analysis (CFA) have probably hindered more widespread adoption. After a bit of discussion of α versus ω, we illustrate the computation of ω using two structural equation modeling programs (Mplus and AMOS) and the…