How to replace value of a variable in one round with its value in a previous round ?

Hi all,

Please consider the following sample data

Code:

* Example generated by -dataex-. To install: ssc install dataex
clear
input float(id round location)
1 1 1
1 2 1
1 3 1
2 1 2
2 2 2
2 3 4
3 1 3
3 2 4
3 3 3
end

In this panel data, location for ids 2 and 3 are not consistent across rounds. I want to make these locations consistent across rounds and equal to the location in round 1. So, location for id 2 would be 2 in all rounds, and for id 3 it would be 3 for all rounds.

I tried

Code:

sort id round
by id: replace location=location[_n-1]|location[_n-2] if location!=location[_n-1]|location!=location[_n-2]

but this simply converted all the locations to 1, which is the first location of id 1.


Would appreciate if someone could suggest how to go about this problem.

Thanks