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Re: st: RE: calculating effect sizes when using svy command

 From Steven Samuels To statalist@hsphsun2.harvard.edu Subject Re: st: RE: calculating effect sizes when using svy command Date Tue, 7 Dec 2010 15:51:06 -0500

```
Dawne Vogt:

-svy: reg- reports an R^2.  Why not use that one?

Steve
sjsamuels@gmail.com

On Dec 7, 2010, at 3:36 PM, Nick Cox wrote:

```
On #2, and setting aside any -svy- complications: If you want a correlation go straight to -correlate-. In any case, the correlation is the same regardless of which of the variables is regarded as response or outcome.
```
Nick
n.j.cox@durham.ac.uk

Vogt, Dawne

```
I have two questions related to calculating effect sizes using svyreg (pweights):
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```
First, when doing unweighted regressions in SPSS, I like to provide effect sizes for each predictor by calculating a correlation coefficient value (r) from the t values provided in the output. I like using r because it is easy for most people to interpret. Can I do the same using svyreg output?
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```
My second question is related to the first. Since there is no correlation option under the svy commands, I have been computing regressions of Y on X and X and Y and using the largest p value of the two sets of results, as recommended elsewhere. I've having trouble figuring out how to convert the results provided in the output to a correlation coefficient though. I noticed that the r value I get by taking the square root of the R squared is different from my own hand calculation of r derived from the t value provided in the regression output [sqrt of (t squared divided by t squared + df). I'm not sure which r is correct (or if either of them are correct).
```
Thanks in advance for any guidance others may be able to offer.

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