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RE: st: Standardized Response Mean. Does Stata calculate this?

 From "Donald Spady" To Subject RE: st: Standardized Response Mean. Does Stata calculate this? Date Tue, 15 Nov 2005 13:04:55 -0700

```Dear All
Thank you for your responses.  I will take them back to my client and we
will work it out.  I don't think that the actual process should be that
difficult.
Again, many thanks
Don Spady

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of James Shaw
Sent: November 15, 2005 12:40 PM
To: statalist@hsphsun2.harvard.edu
Subject: RE: st: Standardized Response Mean. Does Stata calculate this?

The standardized response mean (SRM) is one of several
available effect size indices used to gauge the
responsiveness of scales to clinical change.  The SRM
is computed by dividing the mean score change (i.e.,
follow-up minus baseline) by the standard deviation of
the change.  Other effect size indices use the
standard deviation at baseline (Cohen's D) or the
standard deviation for clinically stable individuals
(responsiveness statistic) in the denominator.

The independent groups' t statistic can be used as an
index of responsiveness in trials comparing treatment
with control.  One simply divides the difference in
change scores between treatment groups by the standard
error of the difference between the group means.

--
Jim

--- Nick Winter <nw53@cornell.edu> wrote:

> Given the name (ES-II), it sounds like an effect
> size of some sort.
>
> That would suggest that it is NOT the t-test from
> the difference of
> means (that is the difference divided by the
> standard error of the
> difference), but rather the difference of means
> divided by the
> standard *deviation* of the difference.  That latter
> is derivable
> from the results of t-test; I don't know if anyone
> has packaged it.
>
>
> I share Nick C's amusement, though.  I suppose as
> long as many
> asterisks are attached to the relevant number,
> people downstream will
> probably be satisfied.
>
> --Nick Winter
>
> At 02:07 PM 11/15/2005, you wrote:
> >This is very intriguing as a little piece of
> >scientific sociology. If neither the client
> >nor the analyst is clear what is meant, why
> >not provide what seems sensible given the
> >problem and the data? Is anyone downstream
> >going to object that you provided the wrong answer?
> >
> >Nick
> >n.j.cox@durham.ac.uk
> >
> >Donald Spady
> >
> > > I am unsure if that is what is meant by a
> Standardized
> > > Response Mean.  I hate to show my ignorance
> about this
> > > but I am flying in the dark and the person who
> asked me
> > > about it wasn't all that clear either.
> >
> >Alan Neustadtl
> >
> > > Isn't this simply the t-statistic from a
> difference of means test?  If
> > > so, -help ttest- should get you going.
> >
> >Donald Spady
> >
> > > Is there any way in Stata to calculate a
> Standardized
> > > Response Mean?  I think it is also known as
> ES-II. It is
> > > the difference between means divided by the
> standard
> > > deviation of the difference. I could find
> nothing about it
> > > using -findit-.
> >
> >*
> >*   For searches and help try:
> >*
> http://www.stata.com/support/faqs/res/findit.html
> >*   http://www.stata.com/support/statalist/faq
> >*   http://www.ats.ucla.edu/stat/stata/
>
>
________________________________________________________
> Nicholas J. G. Winter
> 607.255.8819 t
> Assistant Professor
> 607.255.4530 f
> Department of Government
> nw53@cornell.edu e
> Cornell University
> falcon.arts.cornell.edu/nw53 w
> 308 White Hall
> Ithaca, NY 14853-4601
>
>
> *
> *   For searches and help try:
> *
> http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

James W. Shaw, Ph.D., Pharm.D., M.P.H.
Assistant Professor
Director of Outcomes Research, Jefferson Headache Center
Department of Neurology
Jefferson Medical College
Thomas Jefferson University
Office:  215-955-2097
Cellular:  215-852-3045
Fax:  215-955-1960

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*
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*   http://www.ats.ucla.edu/stat/stata/

*
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```

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