Hi. I'm estimating a regression between municipal GDP per capita - as a dependent variable - and municipal social spending (education spending, health spending, sanitation spending, housing and urban planning) and the lagged dependent variable - as explanatory variables with variables time dummy as follows gdp education health spending housing spending yr* my question is whether I should insert my explanatory variables (X) in the parentheses of gmm style ( ) or ivstyle ( ) xtabond2 gdppercapita laggedgdppercapita educationspeding healthspending housingspending yr*, gmmstyle(laggedgdppercapita, collapse) ivstyle(educationspeding healthspending housingspending yr*) twostep robust or xtabond2 gdppercapita laggedgdppercapita educationspeding healthspending housingspending yr*, gmmstyle(laggedgdppercapita educationspeding healthspending housingspending, collapse) ivstyle(yr*) twostep robust or xtabond2 gdppercapita laggedgdppercapita educationspeding healthspending housingspending yr*, gmmstyle(laggedgdppercapita L.(educationspeding healthspending housingspending), collapse) ivstyle(yr*) twostep robust