Spagplot

[Karen Fink]

I have created a spaghetti plot in Stata, but I am puzzled by the vertical lines at the baseline. Do you have any idea what might be going wrong? The issue is not due to a baseline participant being recorded twice (which could explain it).

[Nick Cox]

Let's assume that the variables are y and t and that you also have an identifier id

scatter y t , by(id) 

should give the individuals' data.

[Rich Goldstein]

my guess is different from @Nick Cox's; you don't show your code (which you should do - please read the FAQ), but my guess is that you are connecting the lines inappropriately; please follow the advice in the FAQ and provide (1) a data example using -dataex- and posted in CODE blocks and (2) show the exact code you used to get the graphs

[Nick Cox]

#2 and #3 aren't contradictory. It could be that you have incomplete histories for some people (?) which are being connected spuriously.