UCL Psychology and Language Sciences


What is Wrong with Cronbach’s Alpha and What to Use Instead

30 August 2018, 4:00 pm–5:00 pm

Event Information

Open to



Professor Chris Brewin


Room 305, 3rd Floor
26 Bedford Way
United Kingdom

Abstract:  When interested in estimating the proportion of scale variance due to a latent variable common to all of a scale’s indicators, the vast majority of applied researchers believe that Cronbach’s alpha is the index of choice. Whereas many methodologists are aware of problems with using Cronbach’s alpha for this purpose, few seem to be aware that there is a better alternative to Cronbach’s alpha.  In this talk, I will discuss the importance of the proportion of scale variance due to a latent variable common to all of a scale’s indicators and the central problem with Cronbach’s alpha for estimating this important parameter.  In addition, an alternative to Cronbach’s alpha - coefficient omegahierarchical – will be introduced and shown to overcome the positive bias often inherent in Cronbach’s alpha.  Finally, I will present the results of simulations testing the accuracy of several different methods for estimating omegahierarchical and conclude with recommendations regarding how to estimate omegahierarchical.

About the Speaker

Richard E. Zinbarg

Professor and Chair, Psychology Department at Northwestern University

Research Interests: Personality traits that might act as vulnerability factors to the development of anxiety disorders including the cognitive and affective processes that might mediate these associations; psychotherapy for anxiety disorders with a main focus currently on generalized anxiety disorder; associations between anxiety disorders and couple functioning including the impact of couple functioning on the outcome of psychotherapy for anxiety disorders; the structure and measurement of anxiety and related affects; measurement and psychometric theory.

More about Richard E. Zinbarg