Dear Stata users,

I am using the System GMM approach for estimation and I want to know whether the code is right or not.
This is the basic equation
ITEMs CEODUAL BDSIZE INDBD SUPSIZE INDSUP SIZE AREC_INVT LOSS AUDFEE GENDER ROA BIG4 AUDOPIN CURR LEV TENURE SWITCH ChangeCPA i.Year i.IND , robust cluster(Stkcd)
Basically, I try to test the impact of corporate governance on disclosure items. The dependent variable is ITEMs and I have 5 independent variables which are CEODUAL BDSIZE INDBD SUPSIZE INDSUP. I also include several control variables including SIZE AREC_INVT LOSS AUDFEE GENDER ROA BIG4 AUDOPIN CURR LEV TENURE SWITCH ChangeCPA. Finally, the year and industry dummies.

I lag the dependent variable and according to the prior studies, they assume that the corporate governance variables are endogenous. So, I write this code and lag them.

xtabond2 ITEMs L.ITEMs CEODUAL BDSIZE INDBD SUPSIZE INDSUP SIZE AREC_INVT LOSS AUDFEE GENDER ROA BIG4 AUDOPIN CURR LEV TENURE SWITCH ChangeCPA i.Year i.IND, gmm(1.ITEMs CEODUAL BDSIZE INDBD SUPSIZE INDSUP) iv(L.CEODUAL L.BDSIZE L.INDBD L.SUPSIZE L.INDSUP SIZE AREC_INVT LOSS AUDFEE GENDER ROA BIG4 AUDOPIN CURR LEV TENURE SWITCH ChangeCPA i.Year i.IND) small twostep robust orthogonal
The questions are:

1- Is the code is right?
2- Should we include all variables that we assume as endogenous in gmm() and all other variables in IV() ?
3- Is the lag above is right or not?