[18827] in s-news-athena
Re: [S] Sample size
daemon@ATHENA.MIT.EDU (Frank E Harrell Jr)
Tue Aug 3 09:21:01 1999
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Date: Tue, 3 Aug 1999 09:14:28 -0400 (Eastern Daylight Time)
From: Frank E Harrell Jr <fharrell@virginia.edu>
To: Giovanni Parrinello <parrinel@bsmed.med.unibs.it>
Cc: s-news@wubios.wustl.edu
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Reply-To: fharrell@virginia.edu
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Giovanni,
In the Hmisc library you will find the spower function which is a
fairly general function to simulate power for complex designs
involving 2 treatments. You can specify a dropout function as a
function of time, a dropin function, and treatment effect function
(hazard ratio), an accrual function, etc. This provides a continuous
version of the Lakatos approach.
Frank
Giovanni Parrinello writes:
>
> Hi,
> Does anyone know how where can I find a function to calculate the Sample
> size for a Survival study with the Lakatos's approch?
> References:
> Lakatos:'Sample size based on the long-rank test in complex critical
> trials' Biometrics 44 1988.
> S-Plus 4.5 for Win95.
> I know that there is a Sas version colled 'SIZE', but I do not know to get
> also it.
> Any help will be greatly appreciated.
> Giovanni Parrinello
> dr. Giovanni Parrinello
> Sezione di Statistica Medica
> Dipartimento di Biotecnologie
> Università di Brescia
> Via Valsabbina, 19
> 25100, Brescia
> Italy
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--
Frank E Harrell Jr
Professor of Biostatistics and Statistics
Division of Biostatistics and Epidemiology
Department of Health Evaluation Sciences
University of Virginia School of Medicine
http://hesweb1.med.virginia.edu/biostat
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