xtpoisson clustered standard errors

[Fredwin Jansen]

Dear members,

If I use the following command, do I correctly cluster standard errors by variable State?

xi: xtpoisson yvariable xvar controlvar controlvar1 i.year i.industry, i(state) fe

Kind regards,

Teun

[Joshua D Merfeld]

According to my understanding of the default in Stata, you need to specify "robust" (or vce(robust)) in order to get the clustered standard errors (which will give you the cluster-robust standard errors using the panel id as the cluster variable). Using the "i()" option only specifies what the panel variable is.

[Nikos Tsileponis]

Hi Teun,

Joshua is absolutely right.

xi: xtpoisson yvariable xvar controlvar controlvar1 i.year i.industry, robust i(state) fe