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I am using a generalized linear mixed model to analyze poisson and binary data. Animals were observed on several moments, so my model should account for that, which is why I am using the GLMM. I am convinced that the model is adequate, however, I do need to correct for overdispersion. However, I cannot find the way to do this in SPSS 20. I am not an SPSS-expert, so I have not found it. Can anyone tell me if it is possible to address overdispersion in SPSS GLMM?

Thank you!

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Is your question only about how to get this done in SPSS? If so, it may be off-topic here (see our FAQ). I don't know if it would fit better on Stack Overflow, though, as I don't know if there are many people who code in SPSS's underlying command language on SO. – gung Aug 22 '12 at 19:34
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What about shifting to negative binomial or use Poisson regression with robust variance estimates? Both are supported by SPSS. – Penguin_Knight Aug 22 '12 at 20:23
In my limited understanding of this topic, the way to adjust for overdispersion is not to do anything within SPSS but instead, after obtaining output, to multiply coefficient standard errors by an adjustment factor. – rolando2 Aug 23 '12 at 3:06

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