Without context this is a shot in the dark, but my guess is this is
referring to something like a logistic regression where the odds ratio
(exponential of the coefficient) refers to the change in odds for the
outcome for a 1 unit change in x.  Now often a 1 unit change in x is very
meaningful, but other times it is not that meaningful, e.g. if x is
measuring the size of diamonds in carats and the data does not span an
entire carat, or x is measured in days and our x variable spans years.  In
these cases it can make more sense to talk about the change in the odds
relative to a different step size than just a 1 unit change in x, a
reasonable thing to use is the change in odds for a one standard deviation
change in x (much smaller than 1 for the diamonds, much larger for the
days), this may be the odds ratio per standard deviation that you mention.


On Tue, Jun 11, 2013 at 7:38 PM, vinhnguyen04x <imvinhs@yahoo.com.vn> wrote:

> Hi all
>
> i have a question:
>
> why and when do we use odds ratio per standard deviation instead of odds
> ratio?
>
>
>
> --
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>
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-- 
Gregory (Greg) L. Snow Ph.D.
538280@gmail.com

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