My code: proc mixed;   class side event subj;   model FA = event side event*side;   repeated event / type=cs subject = subj;   title2 "MIXED"; run; My results:                                                          MIXED                                                   The Mixed Procedure                                                Convergence criteria met.                                                                 Covariance Parameter Estimates                                             Cov Parm     Subject    Estimate                                             CS           subj       0.002596                                             Residual                0.001612                                                     Fit Statistics                                          -2 Res Log Likelihood          -363.5                                          AIC (smaller is better)        -359.5                                          AICC (smaller is better)       -359.4                                          BIC (smaller is better)        -356.6                                             Null Model Likelihood Ratio Test                                               DF    Chi-Square      Pr > ChiSq                                                1         55.28          <.0001                                              Type 3 Tests of Fixed Effects                                                    Num     Den                                     Effect          DF      DF    F Value    Pr > F                                     event            1      30       2.41    0.1312                                     side             1      30       3.61    0.0672                                     side*event       0       .        .       .    I'm just wondering if the missing values for side*event means there's no interaction or if something is wrong with the code/data. Thanks~ Thanks~ ... View more