clear
set mem 100M
set matsize 80
set more off

cd "C:\Users\josh\Documents\My Dropbox\Classes\Econ 174\Assignments\Practice"
log using iv.log

* load an arbitrary dataset from the stata library
webuse hsng2, clear

* Reduced Form
regress rent faminc pcturban, robust
gen rf_coef=_b[faminc]

* First stage
regress hsngval faminc pcturban, robust
gen fs_coef=_b[faminc]

* 2SLS using ivregress
ivregress 2sls rent (hsngval = faminc) pcturban, robust

* 2SLS using predicted values
regress hsngval faminc pcturban, robust
predict pred_hsngval, xb
regress rent pred_hsngval pcturban, robust

* 2SLS using residuals
regress hsngval faminc pcturban, robust
predict resids, resid
regress rent hsngval pcturban  resids, robust

* 2SLS using ratio of coefficients
gen iv_coef = rf_coef/fs_coef
sum iv_coef