Hi, I'm trying to fit a random intercept mixed model with a sp(pow) covariance structure (time is continuous) to quality of life data. When I try to run the code below SAS gives me the following error: "Warning: Stopped because of too many likelihood evaluations." proc mixed data=data cl; class person_id treatment_group; model QOL = QOL_baseline treatment_group time treatment_group*time / solution cl htype=1; repeated / type=sp(pow)(time) subject=person_id r rcorr; random intercept / subject=person_id; run; Can anyone help?
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