I wonder if someone can explain what is the main difference between omega and alpha reliabilities?
I understand an omega reliability is based on hierarchical factor model as shown in the following picture, and alpha uses average inter-item correlations.
What I don't understand is, in what condition, omega reliability coefficient would be higher than alpha coefficient, and vice versa?
Can I assume if the correlations between the subfactors and the variables are higher, the omega coefficient would also be higher (as shown in the above picture)?
Any advice is appreciated!