what variable in the second stage of stata is relevant to the dependent variable can variables be added into the second stage of the stata model should the control variables in the first and second stage be different what variable should be included on the first stage of ols when is the variables used first in stata why does stata use control variables in second stage when does ols need to be used what should the variable be in the ols first stage of stata why are variables in the first stage of stata why are variables in the first stage of stata different than controls should control variables be included in the first stage how can the variable used first ols be different what variable should a model use as the control in the first stage of twosls why are control variables included in first stage of stata? what variables are included first in stata why would variable first stage be different from variable second stage which of the following variable is not a dependent variable in a stata analysis should the variable in the first stage of 2sls be different from the variable in the second stage what is the difference between the first stage of twosls and the second stage of twosls what is first phase variable in 2sls