Hi!
we observed patients at different time points and it is numbered under
'visit' variable as
1,2,3,4,5
And we know the date of each visit (variable named 'date')
I am trying to calculate the number of days between visits for each
patient. Patients can be identified after their studyid.
For example, my aim is to have something as below
studyid visit date days
1001 1 01-01-2000 0
1001 2 15-01-2000 14
1001 3 20-01-2000 5
etc..
days is the new variable i aim to create etc...
Any tips?
Thank you and best regards
ziad
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