Indicating change in a variable across a year

[ChuksManuel]

Hi programmers,

I have a variable assessed in two points (longitudinal data): 2019 survey, FS (coded as 0,1). 2020 survey, FS (coded as 0,1).

I want to create a change variable such that;

An observation with 0 in 2019 who is still 0 in 2020= variable A

An observation with 0 in 2019 who becomes 1 in 2020=variable B

An observation with 1 in 2019 who becomes 0 in 2020= variable C

An observation with 1 in 2019 who is still 1 in 2020=variable D

Is there a way I can code this? Do I need to create a flag variable in both years? 

[Kurt_Bremser · Accepted solution]

Please post a example for your data in a DATA step with DATALINES, so structure and content become more clear.

[ChuksManuel]

Figured it out. Thanks