gsrsb:Group Sequential Refined Secondary Boundary
A gate-keeping procedure to test a primary and a secondary endpoint in a group sequential design with multiple interim
looks. Computations related to group sequential primary and
secondary boundaries. Refined secondary boundaries are
calculated for a gate-keeping test on a primary and a secondary
endpoint in a group sequential design with multiple interim
looks. The choices include both the standard boundaries and the
boundaries using error spending functions. See Tamhane et al.
(2018), "A gatekeeping procedure to test a primary and a
secondary endpoint in a group sequential design with multiple
interim looks", Biometrics, 74(1), 40-48.
