st: treatreg vs ivreg revisited

[Andrea Menclova <andrea.menclova@canterbury.ac.nz>]

Dear Statalist community,

 

I have a “treatment” model with individual-level data (and a large number of observations) where the dependent variable is “birth weight” and the treatment variable is “delivery by a midwife” (versus delivery by an obstetrician).  Having read several previous posts on this listserv (with helpful responses from Mark Schaffer – thanks!), I still can’t decide whether to use treatreg or ivreg to estimate the effect of midwife delivery on infant health. So far, all comments I’ve received from colleagues and readers of my manuscript were focused on the strength/validity of my instruments but only recently someone suggested I could use treatreg and rely on the inverse Mills ratio for addressing endogeneity/selection. Could someone please give me advice about which is preferable?

 

Many thanks in advance,

 

Andrea