The REPEATED statement defines the repeated effect and the residual covariance structure in the mixed model. The residual variancecovariance matrix is denoted as . The repeatedeffect is required and consists entirely of classification variables. The levels of the repeatedeffect must be different for each observation within a subject in order to avoid the singular matrix. The SUBJECT= option is required. The data set must be grouped by subject effect.
Table 49.10 summarizes the options available in the REPEATED statement.
Table 49.10: Summary of REPEATED Statement Options
Option 
Description 

Construction of Covariance Structure 

Defines an effect that specifies heterogeneity in the residual covariance structure 

Identifies the subjects in the residual covariance structure 

Specifies the residual covariance structure (the default is VC) 

Statistical Output 

Displays blocks of the estimated matrix 

Display the Cholesky root (lower) of blocks of the estimated matrix 

Displays the inverse Cholesky root (lower) of blocks of the estimated matrix 

Displays the correlation matrix that corresponds to blocks of the estimated matrix 

Displays the inverse of blocks of the estimated matrix 
You can specify the following options in the REPEATED statement after a slash (/).