PROC GEE ERROR: within effect should be unique

[AmaraEzeamama]

I am trying to run the following program for analysis of repeated measures multinomial data. 

proc gee data=ironstat4;
class tovid anemia_type baseline_anemia_type time_ ;
model anemia_type=baseline_anemia_type / dist=multinomial link=glogit;
repeated subject=tovid /within=time;
run;

subjects are uniquely identified via the variable "tovid".  I have three repeated assessments with periods of assessment represented by "time_).  I simply don't understand this error and/or what I can do to resolve it.  I'd appreciate any thoughts to help me move forward. 

[Reeza · Accepted solution]

Do you have duplicates within subject and time?

You can run a proc freq to check that.

proc freq data=ironstat4;
table tovid*time / out=check (where=(count>1));
run;

If the data set named CHECK is empty it's something else. If not, those records have duplicates for subject time. 

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@AmaraEzeamama wrote:

I am trying to run the following program for analysis of repeated measures multinomial data. 

proc gee data=ironstat4;
class tovid anemia_type baseline_anemia_type time_ ;
model anemia_type=baseline_anemia_type / dist=multinomial link=glogit;
repeated subject=tovid /within=time;
run;

subjects are uniquely identified via the variable "tovid".  I have three repeated assessments with periods of assessment represented by "time_).  I simply don't understand this error and/or what I can do to resolve it.  I'd appreciate any thoughts to help me move forward. 

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[AmaraEzeamama]

Thank you Reeza: This check allowed me to solve the problem. So thankful for your assistance!