My dependent variable is count data and for explanatory analysis we used a negative binomial regression. One variable is endogenous and we would like to instrument it. However, in Stata there is only one (user-written) program for IV regressions when the dependent variable is count data by nature, namely ivpois
. It employs GMM, though. For R, there are even less, namely zero, packages available that deal directly with such IV regressions.
Therefore I thought about using standard 2SLS methods (ivreg()
for R or ivreg
/ivreg2
for Stata). Can anything go wrong if we do so?
ivpois
for Stata? $\endgroup$