Generate a binary treatment indicator for DiD

[Anna Fran]

I have to generate a binary treatment indicator for having a water supply system in a municipality in a given year.

I have the following variables:
- year
- wateryear: the year in which a municipality introduced fresh water supply systems
- kreisid: unique identifier for municipalities

[Nick Cox]

gen wanted = year >= wateryear if !missing(year, wateryear)

may help.