Hi,

I am working with longitudinal data in long format. Idnr is identification number and time is timepoint (baseline, follow-up1, etc.). When data on follow-up measurements are missing, there is no "row of observations". I would like to create equal amount of observations for each id number. So each id number should have 5 "rows" of observations, even if the data is missing. What is the command for creating these observations? Thank you.
Idnr time
1 1
1 2
1 3
2 1
3 1
4 1
4 2
4 3
4 4
4 5

Idnr time
1 1
1 2
1 3
1 4
1 5
2 1
2 2
2 3
2 4
2 5
3 1
3 2
3 3
3 4
3 5
4 1
4 2
4 3
4 4
4 5