Use the reshape command to switch from wide to long: reshape long [variable_prefix], i([id_variable]) j([time_variable]) 2. Declare Panel Structure
models. These models allow researchers to control for time-invariant variables that cannot be measured directly, such as cultural factors or stable business practices, by focusing solely on "within-entity" variation. Automatic Data Management stata panel data exclusive
xtreg y x1 x2 i.year, fe robust // cluster-robust SE xtreg y x1 x2 i.year, fe vce(cluster id) // equivalent xtreg y x1 x2, fe vce(bootstrap, reps(200)) // alternative Use the reshape command to switch from wide