[R] R equivalent of S+SeqTrial?

[francogrex]

Thanks again; It's ok I'm using the ldBands function now, the ld98.exe is
just a small file to download into the path. I can calculate the alpha
spending function and determine (given the Z statistics of my observations)
if at the interim analysis the null hypothesis is to be rejected or not.
But Does this function allow me to calculate the conditional power given the
accumulating data? (I know they give the exit probabilities but is it those
that I need?) and in the documentations they make a reference to another
function using a bayesian method (Gaussian Bayesian Posterior and Predictive
Distributions), but i'm not comfortable yet using the bayesian methods.


On Wed, 2007-03-28 at 10:49 -0500, Douglas Bates wrote:
> On 3/28/07, Marc Schwartz <marc_schwartz at comcast.net> wrote:
> > On Wed, 2007-03-28 at 02:42 -0700, francogrex wrote:
> > > Does anyone know of an R package that is equivalent of S+SeqTrial for
> > > analysis of clinical trials using group sequential methods? Thanks.
> >
> > I don't know that there are fully functional equivalents, but you might
> > want to look at the following:
> >
> > 1. The GroupSeq package on CRAN:
> >
> >   http://cran.r-project.org/src/contrib/Descriptions/GroupSeq.html
> >
> >
> > 2. The ldBands() function in Frank Harrell's Hmisc package on CRAN:
> >
> >   http://biostat.mc.vanderbilt.edu/s/Hmisc/html/ldBands.html
> >
> > This also requires the ld98 executable, which is available from:
> >
> >   http://www.biostat.wisc.edu/landemets/
> 
> There is also the ldbounds package on CRAN for calculating Lan-DeMets
> boundaries.  It was prepared by students working with Dave DeMets and
> does not require the ld98 executable.

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