# Re: st: Adding R-Squared to sw command output

 From Richard Williams To statalist@hsphsun2.harvard.edu Subject Re: st: Adding R-Squared to sw command output Date Thu, 27 May 2004 10:17:20 -0500

At 03:53 PM 5/27/2004 +0100, Rena Jenkins wrote:
Is there a Stata programming guru out there who could help me modify the sw command so that the R-squared of the model is output at each stage? (I am just running a linear regression.) i.e. to print the value of e(r2) at each stage.

So that when you run something like
sw regress y x1 x2 x3, pe(0.05)

begin with empty model
p = 0.0032 < 0.0500 adding x2
p = 0.0153 < 0.0500 adding x1
p = 0.0424 < 0.0500 adding x3

You get something like:
begin with empty model
p = 0.0032 < 0.0500 adding x2, R-squared = 0.2018
p = 0.0153 < 0.0500 adding x1, R-squared = 0.2523
p = 0.0424 < 0.0500 adding x3, R-squared = 0.2852
Rather than replacing sw.ado, I would suggest copying it as sw2.ado, and place it in c:\ado\personal. Change the line that says "program define sw" to "program define sw2". Then, search for the line that includes the word "adding". Replace it with

di in gr " < " %5.4f \$HSW_Pe " adding " in ye "\${HSW_`k1'}" in gr ", R^2 = " in ye e(r2)

This works with ols regression; sw2 would need further coding if you wanted to make it more general than that. I get output like

. sw2 reg income educ jobexp black, pe(.10)
begin with empty model
p = 0.0000 < 0.1000 adding educ, R^2 = .65926337
p = 0.0000 < 0.1000 adding jobexp, R^2 = .81626138
p = 0.0000 < 0.1000 adding black, R^2 = .82641678

If you really want blow by blow accounts of what is happening in a stepwise regression, SPSS is better.

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Richard Williams, Notre Dame Dept of Sociology
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