sum up series in panel data set

[stefanp]

I have a panel data set which contains several series. I need to sum up the values for some cross sections (across identifiers, not time) depending on some specific conditions. I thought of something like this:

Code: Select all

smpl @all if condition_a=1 series test=@sum(series_a)

However, the values of test appear to be summed up across cross sections and over time. Is it necessary to write a loop which repeats the above procedure for each period separately or is there a simple command to do that?

[EViews Gareth]

Use @sumsby(series_a, @crossid) (or replace @crossid with the name of your cross-section identifier series).