I'm writing a dynamical script which enables the user to select different scales to analyze their reliability. However, I want adress the overall reliability in some kind of global variable. Since the user might select multiple scales which are not related in any empirical or theoretical way, I'm considering just using the mean of the cronbach's alpha value of the selected scales. Is it legitimate to do so?

  • $\begingroup$ What have you learned so far -- anything that would make you lean one way or the other? Anything specific that you'd like comments on? $\endgroup$
    – rolando2
    May 14, 2017 at 21:11

1 Answer 1


As internal consistense is a correlation the average across the values is not legit.

  1. You should use Fisher's z Transformations on your cronbach's alpha values
  2. Average those z values
  3. Tranform average z back into cronbach's alpha value

For more details please have a look at http://www.tandfonline.com/doi/abs/10.1080/00221309809595548

  • $\begingroup$ The procedure per se is valid (btw thanks for the reference, I didn't know this one), but it does not answer the question if averaging Cronbach's alpha's over multiple scales makes any sense (I'd rather argue that it does not). $\endgroup$
    – Tim
    Jun 19, 2017 at 9:22
  • $\begingroup$ Totally with you, that in most cases it doesn't make sense to average the Cronbach’s alpha across non-related scales. $\endgroup$
    – Gregor Ma
    Jun 19, 2017 at 9:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.