Cronbach’s Alpha coefficients - How to interpret Cronbach’s Alpha

Cronbach’s Alpha coefficients - How to interpret Cronbach’s Alpha

Reliability tests, like Cronbach’s alpha, are most commonly used to see if questionnaires with multiple Likert scale questions are reliable. These questions are designed to measure latent variables. A latent variable is a hidden or unobservable variable, like a person’s conscientiousness, neurosis or openness. These variables are notoriously difficult to actually measure; Cronbach’s alpha will tell you if the test you have designed is accurately measuring the latent variable you are interested in.

Cronbach's alpha simply provides you with an overall reliability coefficient for a set of variables (e.g., questions). If your questions reflect different underlying personal qualities (or other dimensions), for example, employee motivation and employee commitment, Cronbach's alpha will not be able to distinguish between these. In order to do this and then check their reliability (using Cronbach's alpha), you will first need to run a test such as a principal components analysis (PCA). 

Guidelines for identifying significant Cronbach’s alpha coefficients