Re: {MEDSTATS} Confidence interval for ratio of independent binomial proportions

[Frank Isackson]

I'm willing to be that this is a pretty good indicator of the agency's thinking:

New Tests for Null Hypothesis of Non Unity Ratio of Proportions
Author: Kallappa M. Koti a
Affiliation: a United States Food and Drug Administration, New Hampshire Avenue, Silver Spring, Maryland, USA

DOI: 10.1080/10543400601177426
Publication Frequency: 6 issues per year
Published in: Journal of Biopharmaceutical Statistics, Volume 17, Issue 2 March 2007 , pages 229 - 245

Frank Isackson

-----Original Message-----
>From: John Uebersax <jsueb...@gmail.com>
>Sent: Nov 13, 2009 12:15 PM
>To: MedStats <meds...@googlegroups.com>
>Subject: {MEDSTATS} Confidence interval for ratio of independent binomial proportions
>
>
>Can anyone give advice on the state of the art for estimating the
>confidence interval for the ratio of two independent binomial
>proportions (e.g., CI for a likelihood ratio)?
>
>An FDA guidance seems to be recommending 'exact' confidence intervals
>here, though I'm not sure what they mean -- maybe something available
>with StatXact.
>
>However StatXact 8 (p. 336 f. in the manual) has at least three
>different methods for estimating the CI of a ratio of independent
>binomial proportions, and their results don't always agree.
>
>Possibly complicating things, I have data with large denominators and
>small numerators (i.e., for each of the two individual proportions
>whose ratio is considered). My test data required large cpu times
>(e.g., 4 minutes).
>
>Basically I have two questions:
>
>1. Is there consensus that 'exact' CIs should be used here if
>possible?
>2. With large denominators and small numerators, can asymptotic
>formulas can be used instead of exact methods; or would the small
>numerators control the decision?
>3. Is there a recent review of this general topic (exact tests for a
>ratio of independent proportions)?
>
>Any suggestions or pointers would be appreciated.
>
>Ray Koopman (if it's the same person) has published in this area; I
>wonder if he's following the discussion group.
>
>--
>John Uebersax PhD
>http://www.john-uebersax.com
>>

[kornbrot]

Do you have a pdf you could send me? Would be much appreciated. My uni can’t afford inforam any more and Koit is extraordinarily reticent about hise email – FDA policy?

Many thanks

Diana

---

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