McDonald’s Omega Hierarchical

Omega hierarchical, named by Roderick McDonald, is a measure of the extent to which the total score on a test or scale reliably measures a single, general construct that influences all of the total score’s components (typically, scores on individual items). As such, omega hierarchical can be considered a type of internal consistency reliability (or composite reliability) measure. Unlike the more commonly reported Cronbach’s coefficient alpha, omega hierarchical is an appropriate reliability estimate when a test has a multidimensional structure (i.e., there are multiple systematic influences on the item responses), but a researcher’s interest lies in the reliability of an overall score for the test. Reliability estimation is fundamental to research methods because reliability quantifies the quality of a measurement; without accurate measurement, research results ...