I need to test validity of measurement scales in my survey.
1) Is it true that both can be used to test measurement validity?
2) Or there are some types of validity that can be tested with EFA and some that – with CFA?
3) What is the best solution – which one should be used or both?
P.S. I have survey consisting of n-items (n-questions). Survey is related to consumer attitudes and behavior. The survey was constructed to measure 6 different constructs, each construct consist of different number of items (questions). I am writing a theoretical review of statistical methods that would be used to analyse the survey data. This is my first survey, I never did construct validity before, just read about it.
Best Answer
In the end, in order to validate that your instrument does in fact measure 6 specific constructs, you will need to test this model with confirmatory factor analysis (CFA). Exploratory factor analysis (EFA) may be informative in the early stages of evaluating an instrument, e.g. if you are not sure if your instrument measures 4, 5 or 6 dimensions. However, CFA is more informative about sources of misfit and potential methods effects. This includes cases of items with very similar wording, or reverse items. Such pairs of items have inflated loadings and may change the factor solution. CFA will notify you of such cases, EFA will not. In any case, if you want to test validity, you need a hypothesis, in this case a model, which you put to the test and potentially confirm.