# Re: st: regress and then extrapolate with new dependent vars but same coefficients

 From Richard Williams To statalist@hsphsun2.harvard.edu Subject Re: st: regress and then extrapolate with new dependent vars but same coefficients Date Wed, 19 Jul 2006 11:12:34 -0500

```At 09:56 AM 7/19/2006, Olga Gorbachev Melloni wrote:
```
Hello,

I need to run an exercise in which after running a regression and predicting the y_hat, I need to replace one of the dependent variables with zeros and then use the saved coefficients to predict a hypothetical value for y_hat(given x1==0), in order to compare the predicted values from these two exercises.

Does any one know how to do this quickly, without saving all the coefficients and manually predicting for the second step? I am running a regression with 174 dependent variables (mostly dummies) and it would take some time to predict manually.

I've checked on the faq for this and was unable to find anything, i might have overlooked the answer and apologize in advance if it has been asked and answered already and would appreciate any references if so.
One way is to use the adjust command.

reg y x1 x2 x3
predict yhat1

Another way:

clonevar newx1 = x1
reg y newx1 x2 x3
predict yhat1
replace newx1 = 0
predict yhat2

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Richard Williams, Notre Dame Dept of Sociology
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