How to add an extra year to an existing dataset

[Saleh sharmah]

Dear members
I have a dataset spanning from 2005-2019 and I would like to add 2004 to the year variable by company_id to append the 2004 companies data to the existing dataset.

what’s stata command to achieve the above task ?
thanks

[Nick Cox]

If I understand this correctly your main dataset already has a year variable. Even if your 2004 dataset has no year variable, you just need to go within that dataset

gen year = 2004

and then append, Naturally use a different variable name if your main dataset is using Year or something else.

Not quite equivalent is to append any way and go then go in the combined dataset

replace year = 2004 if year == .

That''s not quite equivalent if there are missing values in the main dataset.

[Saleh sharmah]

Thanks Nick for your help. I thought it was more complicated
than this .