ssc install xtabond2 xtabond2 y L.y x1 x2, gmm(L.y, lag(2 4)) iv(x1) robust twostep
Panel data is a type of data that combines cross-sectional and time series elements. It consists of observations on multiple individuals, firms, or countries at multiple points in time. This data structure allows researchers to examine changes over time, as well as differences across individuals or groups. Panel data is widely used in econometrics, finance, sociology, and other fields. stata panel data exclusive
mixed y x1 x2 || panel_id: