The mean that defines success at the final analysis. Typically chosen to be the minimal detectable difference, i.e. the critical on the scale of the effect size of interest corresponding to the significance level at the final analysis.
finalSE
(Known) standard error at which the final analysis of the study under consideration takes place.
interimmean
Mean of the data.
interimSE
(Known) standard error of interimmean.
priormean
Prior mean.
propA
Proportion of subjects randomized to arm A.
...
Further arguments specific to the chosen prior (see bpp for examples).
Value
Value of the function, a real number.
References
Rufibach, K., Jordan, P., Abt, M. (2016a).
Sequentially Updating the Likelihood of Success of a Phase 3 Pivotal Time-to-Event Trial based on Interim Analyses or External Information.
J. Biopharm. Stat., 26(2), 191--201.