Dear all,

I have cross-sectional data that include siblings. Now I need to run an analysis that using the sibling fixed-effect approach. The identifier variable I have is the personal ID (id) and family ID (famid, people within the same family are all siblings).
To control the sibling effect, I plan to use the following codes.

reg y x i.famid
areg y x, absorb(famid)
reghdfe y x, absorb(famid)

I assume these three codes will give the same results. Am I correct in modeling the sibling fixed effect?

I really appreciate any help you can provide.