[R] Triangular Test

Marc Schwartz marc_schwartz at me.com
Tue Feb 21 17:19:23 CET 2012

On Feb 20, 2012, at 7:45 AM, kende jan wrote:

> Hello,
> I would like to perform triangular test for clinical trial with R.
> can you help me please ?
> Jan


I am not aware of any specific implementations of Whitehead's Triangular Test[1] in R, though somebody else may be aware of something locally. There are implementations in SAS of course, either using Whitehead's own PEST (http://www.maths.lancs.ac.uk/department/research/statistics/mps/pest) or the PROC SEQDESIGN implementation, neither of which are free.

There appears to be an online implementation, at least of potentially limited scope here:


but it would be reasonable to validate the implementation before proceeding with use.

For R, there are other group sequential boundary and alpha spending based methods implemented and there is a CRAN Task view that you might find helpful, which links to R packages that implement some of these procedures:


I have used Keaven Anderson's gsDesign package for example, which includes a nice document with worked examples of designs and subsequent monitoring.


Marc Schwartz

[1]  Whitehead J. The Design and Analysis of Sequential Clinical Trials. 
     Revised 2nd Edition. Chichester: Wiley, 1997

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