Hi,
I am learning to use your gsDesign package! I have a question about Pocock and
OBF boundary. As far as Iunderstand, these 2 boundaries require equal spacing
between interim analyses(maybe this is not correct?). But I can still use
gsDesign to run an analysisbased on unequal spacing:
gsDesign(k=2,test.type=2,timing=c(0.75,1),alpha=0.05,sfu='Pocock')Symmetrictwo-sided
group sequential design with90 %power and 5 % Type I
Error.Spendingcomputations assume trial stops if a bound is crossed.
Sample Size AnalysisRatio* Z Nominal p Spend 1 0.796
1.82 0.0346 0.0346 2 1.061 1.82 0.0346 0.0154 Total
0.0500 ++alpha spending:Pocockboundary.*Sample size ratio compared
to fixed design with no interim Can anyone share some light whether the above
analysis is stillvalid? Or for unequal spacing, I have to use Lan-Demet’s error
spendingfunction approximations? Thank you,
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