Hi everyone, I am trying to calculate number of years from baseline visit by subjects. Date format is mmddyy10. When I try the code below, it does the job for the first visit date (baseline) but not for the following visit dates (see results table at the end): proc sort data= have; by ID Test_Date; run; data want; set have; length Visit 8.; by ID Test_Date; retain first.Test_Date; if first.ID then do; first.Test_Date = Test_Date; end; Visit = intck('year',first.Test_Date,Test_Date)+1; format first.Test_Date Test_Date mmddyy10.; run;   ID Test_Date Visit 1 10/25/2011 1 1 11/05/2013 54 1 11/03/2015 56 1 11/07/2017 58 2 05/04/2011 1 3 06/02/2011 1 3 06/10/2013 54 3 06/15/2015 56 3 06/08/2017 58 Any suggestion will be much appreciated, Thank you! JJ   ... View more

Hello everyone,   I have a dataset with subjects (ID) that have the same number of follow-ups (Follow-up) with a result in a test (Test with 0 being negative and 1 being positive). I want to create a new variable (Test_Positive) with last available follow-up in Test variable. I want the Test_Positive variable to have all follow-ups as 0 or 1 according to last available Test value. The simulation below may be more informative. Please see below:   HAVE:   ID Follow-up Test 1 1 0 1 2 . 1 3 1 1 4 1 2 1 0 2 2 0 2 3 0 2 4 0 3 1 1 3 2 1 3 3 . 3 4 .     WANT:   ID Follow-up Test Test_Positive 1 1 0 1 1 2 . 1 1 3 1 1 1 4 1 1 2 1 0 0 2 2 0 0 2 3 0 0 2 4 0 0 3 1 1 1 3 2 1 1 3 3 . 1 3 4 . 1     I have tried the following code without success (see output at after code):   proc sort data = have; by Follow-up; run; data want; set have; by Follow-up; Test_Positive =  . ; if last.Test then Test_Positive = last.Test; if last.Test = . then Test_Positive = .; else Test_Positive = coalesce(Test,Test_Positive); retain Test_Positive; run;   OUTPUT (the error is in 2 first rows where Test_Positive should be 1):   ID Follow-up Test Test_Positive 1 1 0 0 1 2 . 0 1 3 1 1 1 4 1 1 2 1 0 0 2 2 0 0 2 3 0 0 2 4 0 0 3 1 1 1 3 2 1 1 3 3 . 1 3 4 . 1     Thank you very much for any help! JJG ... View more

Hello! I have a dataset on which I need to create a "visit" variable (want) with serial numbers according to all available not missing values in another variable (var). The dataset is sorted by ID and Timepoint variables. Below are the 3 variables in the dataset (ID, Timepoint and Var) and last column is what I am looking for (want).   ID TimePoint Var Want 1 1 . . 1 2 5 1 1 3 . . 1 4 7 2 1 5 4 3 2 1 . . 2 2 9 1 2 5 . . 3 1 . . 3 2 8 1 3 3 3 2 3 4 5 3 3 5 . . 3 6 5 4   I have tried the following code without success on getting serial number variable (see code and output below): proc sort data=have; by ID TimePoint; run; data want; set have; want + 1; if Var > 0 then want = 1; else want = .; run; ID TimePoint Have Want 1 1 . . 1 2 5 1 1 3 . . 1 4 7 1 1 5 4 1 2 1 . . 2 2 9 1 2 5 . . 3 1 . . 3 2 8 1 3 3 3 1 3 4 5 1 3 5 . . 3 6 5 1 Thank you for any input regarding this matter! JJG   ... View more