Since GLIMMIX does not support the REPEATED statement as such, instead using _residual_ in a random statement, you might try: proc mixed data=sasuser.w_400_2012 method=reml; class ID track_type; model l_time = fixed_date track_type / s residual outp=work.resid; random int fixed_date / subject=ID; random _residual_ / subject=ID type=SP(POW)(fixed_date); lsmeans track_type / diff; run; Now when you shift over to a non-Gaussian distribution, take care, as most of the distributions are such that the means and variances are not independent, and perhaps should be modeled as G-side "repeated" rather than R-side "repeated".  See Walt Stroup's Generalized Linear Mixed Models (2013) for an interesting take on this.  A great book, with tons of GLIMMIX examples. Steve Denham ... View more