I'm trying to fit a linear structural equation (along with a nonlinear measurement model) in a panel data setting. I have noticed that the commands sem and gsem produce very different estimates on the same model specification, and I don't understand why.
Here's a stylized example (without a measurement model):
The coefficients from the sem command are close to the ones from the differenced OLS regression; those from the gsem command differ a lot. Can anyone explain why?
Here's a stylized example (without a measurement model):
Code:
webuse nlswork, clear
reg d.ln_wage d.hours d.union
sem (ln_wage <- hours@h union@u FE@1 _cons@c) ///
(l.ln_wage <- l.hours@h l.union@u FE@1 _cons@c)
gsem (ln_wage <- hours@h union@u FE@1 _cons@c) ///
(l.ln_wage <- l.hours@h l.union@u FE@1 _cons@c) ///
, listwise
