Compare observation first time event occurs with previous observation in panel data

[Jakob Poulsen]

I need some help (code) finding a solution for the following problem:

I have a longitudinal dataset with a variable number of visits for each patient (id). I want to compare different outcomes the first time an event occurs (kostvejl == 1) with the patient’s previous visit. How do I generate a variable that identifies (tags) the first observation where the event occurs (ie “after”) AND the previous observation (ie “before”) for each id - no matter if the event occurs again or not?

Thanks in advance!


id kostvejl visit
2 0 1
2 0 0
2 0 2
2 1 3
5 0 1
5 0 2
5 0 3
5 0 0
5 1 4
6 0 0
6 0 1
6 1 2
8 0 3
8 0 1
8 0 0
8 1 2

[Øyvind Snilsberg]

perhaps,

by id (visit), sort: gen wanted = kostvejl == 1 | kostvejl[_n+1] == 1

[Jakob Poulsen]

Thanks for the quick reply. Almost what I wanted :-).

Is it possible to assign different values to the new variable, eg "before" =1 and "after" = 2?

Thanks!

[Nick Cox]

See the concurrent thread https://www.statalist.org/forums/for...-certain-value including resources linked there.