Are nearly identical QIC scores considered equal?

Posted by titopuente on Jul 16, 2012; 3:54am
URL: http://spssx-discussion.165.s1.nabble.com/Are-nearly-identical-QIC-scores-considered-equal-tp5714238.html

I am using QIC (Quasilikelihood under the Independence model Criterion) to evaluate different correlation matrices in a GEE (using identical covariates in all models). I have 2 scores: 474.381 and 474.375.

QIC is in the smaller is better format, but with such minimal differences at what point would it be worthwhile to consider these two model fits to be identical? Is the "smaller is better" so strong that even a 0.006 difference is enough for one correlation structure to be clearly favored over another?

(A further bit of information, the QICc (465.957) for the larger QIC is smaller than the QICc (465.961) for the smaller QIC. As far as I understand it, QICc is only meant for choosing between covariates given a correct correlation matrix, but I thought I would include this info as well in case this might somehow be of use in a tiebreaker situation, if that is indeed what I have here.)

Thanks for looking.