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

[Steven Samuels <sjsamuels@gmail.com>]

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):

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?

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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