Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: st: equivalence limit-thanks


From   Ricardo Ovaldia <ovaldia@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: equivalence limit-thanks
Date   Sun, 16 Aug 2009 09:47:47 -0700 (PDT)

Thank you very much Joseph. That is the information that I needed.

Ricardo
Ricardo Ovaldia, MS
Statistician 
Oklahoma City, OK


--- On Sun, 8/16/09, Joseph Coveney <jcoveney@bigplanet.com> wrote:

> From: Joseph Coveney <jcoveney@bigplanet.com>
> Subject: RE: st: equivalence limit
> To: statalist@hsphsun2.harvard.edu
> Date: Sunday, August 16, 2009, 10:49 AM
> Ricardo Ovaldia wrote:
> 
> I am still trying to figure how to do an equivalence test
> in Stata.
> All I have is a 2x2 table (Treatment x outcome). I can use
> -cs- or -rdci-
> to get the CI, but how do I compute the equivalence limit
> assuming delta=25%,
> for example?
> 
> Also, can -pkequiv- be trick into doing this analysis?
> 
> --------------------------------------------------------------------------------
> 
> If your delta is 25% for a risk difference (difference in
> proportions), then you
> can reject the null hypothesis of nonequivalence in favor
> of the alternative
> hypothesis of therapeutic equivalence if the confidence
> interval (CI) from -cs-
> (Wald) or -rdci- (various other methods) lies between -0.25
> and +0.25.  
> 
> For equivalence (as opposed to "noninferiority"), a 90% CI
> is conventionally
> used.  This corresponds to a two, one-sided test
> (TOST) method with alpha =
> 0.05.
> 
> So, set -level- at 90% for -cs- or -rdci- (whichever
> command you choose), and if
> the displayed CI is between the limits that you set for
> equivalence (e.g., -0.25
> to +0.25, in your example), then you can declare
> bioequivalence.
> 
> Joseph Coveney
> 
> 
> 
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
> 


      

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index