Hi,
I'm fitting a generalized estimating equation-type model by specifying the empirical model option in proc glimmix. I am using this in order to model spatial autocorrelation among residuals. The model response is 0/1 and is modeled with a binomial distribution. I know that proc genmod outputs Pan's QIC (quasilikelihood version of AIC) but proc genmod does not (to my knowledge) include the spatial modeling options of glimmix. Has anyone found a way to extract or calculate QIC based upon glimmix model output? I could potentially "borrow" the fitted correlation structure from glimmix and use it as a user-defined correlation structure in genmod, and then get QIC from genmod. However, my data set is quite large with >100 spatial clusters and so handling this seems it would be quite tricky. The empirical option is being used because without it my machine runs out of memory in its efforts to populate a huge matrix that includes the correlation among all data points, even the very distant. My data is quite "cheap" and I have discarded many points (it is satellite imagery). So, for now I am simply validating with an independent data set for model comparison purposes. I believe this gets at the purpose of AIC, but you know how some reviewers are with their insistence upon including the latest buzz word they've latched ahold of. And for a few, it seems "information theoretic" is it. Any guidance is appreciated.-Seth
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