Meeting assumptions in the estimation of reliability

Abstract

Researchers and psychometricians have long used Cronbach’s α as a measure of reliability. However, there have been growing calls to replace Cronbach’s α with measures that have more defensible assumptions. One of the most common and straightforward recommended reliability estimates is ω. After a review of reliability and its estimation in Stata, I introduce the community-contributed command omegacoef. This command reports McDonald’s ω in a format similar to the base alpha command. omegacoef provides Stata users the ability to easily compute estimates of reliability with the confidence that the necessary statistical assumptions are met.