Hello everyone, I'm new to Stata programing and need some help.

I'm currently cleaning and adjusting some variables hat I'll need to use on my models and one of them is the number of members living in the interviwed household.

I criated a ID variable (idom) to give each household a specific number based on serials, controls, etc.

This count variable already exists for some years, but not for the entire datased. I'am basically trying to recreate it.

Here is a sample of what I have:

- idom is the ID that I created for each member of an specific household and v4741 is the variable with how many members this household has. I want to recreate the variable v4741 counting how many times this specific ID appears.


Obs. idom v4741
----------------
7593667. 400713 6
7593668. 400713 6
7593669. 400713 6
7593670. 400713 6
7593671. 400713 6
7593672. 400713 6
----------------
7593673. 400714 4
7593674. 400714 4
7593675. 400714 4
7593676. 400714 4
----------------
7593677. 400716 4
7593678. 400716 4
7593679. 400716 4
7593680. 400716 4
----------------
7593681. 400717 5
7593682. 400717 5
7593683. 400717 5
7593684. 400717 5
7593685. 400717 5
----------------
7593686. 400718 3
7593687. 400718 3
7593688. 400718 3
----------------
7593689. 400719 2
7593690. 400719 2
----------------
7593691. 400720 5
7593692. 400720 5
7593693. 400720 5
7593694. 400720 5
7593695. 400720 5

Since my dataset has more than 7.5 million observations I think it's better to handle this on Stata, but this is something that I could make on Excel with a 'countifs' formula.

Any tips to share?

Thank you!