Can you copy in the error message? The random statement that it looks like you are using will fit separate unstructured matrices for each level of situation which is the dependent variable, and while that might work (I don't know as I've never seen that error and so have never used that syntax), it also greatly increases the number of parameters to be estimated, and hence the need for a LOT more data to get good values. As far as moving to a binary response, I think that will really help. However, to really get things to work you may have consider "collapsing" the data to something that looks like a successes/trials syntax for each timepoint, moving to dist=binomial, and identifying something other than ID as the subject. Steve Denham
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