Defines a covariance structure for random effects in a linear mixed model fitted by REML.
Correlated error models
Lists the random model terms to which a covariance structure is to be applied. Select the random model term that you want.
Specifies whether the covariance structure is to be defined as a single structure for the whole term, or if it is to be constructed as a direct product of matrices corresponding to the factors in the model term.
Once a term is specified, a covariance model can be selected for each factor or the whole term, as required:
- autoregressive order 1 or 2
- moving average order 1 or 2
VSTRUCTURE directive in command mode for a wider range of covariance models, additional options, and further information about the models. In particular, repeated use of VSTRUCTURE enables covariance models to be specified for multiple model terms.