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From |
"Joseph Coveney" <jcoveney@bigplanet.com> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: equivalence limit |

Date |
Mon, 17 Aug 2009 00:49:21 +0900 |

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/

**Follow-Ups**:**RE: st: equivalence limit-thanks***From:*Ricardo Ovaldia <ovaldia@yahoo.com>

**References**:**st: equivalence limit for an inferiority test***From:*Ricardo Ovaldia <ovaldia@yahoo.com>

**Re: st: equivalence limit***From:*Ricardo Ovaldia <ovaldia@yahoo.com>

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