Re: [R] lme between-group and within-group covariance

I will try to make this more precise. In the lme() function, the "correlation" argument allows the user to specify a within-group correlation structure, i.e. the structure of the Lambda matrix using the mixed model notation in Pineiro and Bates. What I want to do is specify a distinct structure fo

[R] lme between-group and within-group covariance

Dear R users, I would be interested in using the lme() function to fit a linear mixed model to a longitudinal dataset. I know this function allows for the specification of a within-group covariance structure. However, does it allow for the explicit specification of a between-group covariance stru