Solved – Is logistic regression still valid where there are repeated measurements and generalized estimating equations is the real deal

generalized linear modellogisticregression

I have a model with a binary dependent variable (DV) and 5 independent variables, all of which are matched (each person, twice).

I think since these matched INDEPENDENT variables can be considered "repeated-measures", generalized estimating equations (GEE) is the best approach here. However, I have used binary logistic regression.

Do you think this analysis is valid? Or is it just of lower power or less elegant than GEE?

I can handle a lower power or less elegance, but not invalid. By "invalid" I mean where some assumptions are not met and the test is incorrect.

My guess is that since binary logit discards the correlations between the repeated measures, it is a special case of repeated measures with zero correlation. So it might still be valid, but less useful than GEE.

Am I right?

Besides, I doubt if matching the independent variables is considered repeated measures. I am confused.

Best Answer

I agree with @andrea that it is common to see "matched individuals by some independent variables", but not "matched independent variables".

If individuals are matched, it is repeated measures. Zero correlation can happen but is rare, so the usual logistic regression you used may not be valid. The conditional logistic regression or GEE is robust to handle the correlation within repeated measures.

The difference between conditional logistic regression and GEE is the interpretation, where the former getting the subject specific estimate and the latter the population average estimate.

Related Question