Help with calculating differences between the same observation

[Joseph Ejima]

Hello, I am currently working on the effect of covid 19 on unemployment and I have four waves (2018,2019,2020,2021) of household survey for the same households. Currently, I am having a little bit of challenge calculating the change in different outcome variable across two different rounds. For example if I take individual 1001, I want to look at the change in the income of this individual in 2018 and 2019.

[Øyvind Snilsberg]

maybe the following example is useful,

* Example generated by -dataex-. For more info, type help dataex
clear
input int(id year) byte income
1001 2018 20
1001 2019 21
1001 2020 22
1001 2021 23
1002 2018 27
1002 2019 26
1002 2020 25
1002 2021 24
end

by id (year), sort: gen wanted = income - income[_n-1]