gs_prob: Group sequential boundary crossing probabilities
In keaven/gsdmvn: Group sequential design with non-constant effect

Description Usage Arguments Details Value Examples

Group sequential boundary crossing probabilities

1	gs_prob(theta, upper = gs_b, lower = gs_b, upar, lpar, info, r = 18)

`theta`	natural parameter for group sequentia design representing expected drift at time of each analysis
`upper`	function to compute upper bound
`lower`	function to compare lower bound
`upar`	parameter to pass to upper
`lpar`	parameter to pass to lower
`info`	statistical information at each analysis
`r`	Integer, at least 2; default of 18 recommended by Jennison and Turnbull

Approximation for theta is based on Wald test and assumes the observed information is equal to the expected.

A 'tibble' with a row for each finite bound and analysis containing the following variables: Analysis analysis number Bound Upper (efficacy) or Lower (futility) Z Z-value at bound Probability probability that this is the first bound crossed under the given input theta approximate natural parameter value required to cross the bound

# Asymmetric 2-sided design
gs_prob(theta = 0, upar = rep(2.2, 3), lpar = rep(0, 3), upper=gs_b, lower=gs_b,  info = 1:3)
# One-sided design
x <- gs_prob(theta = 0, upar = rep(2.2, 3), lpar = rep(-Inf, 3), upper=gs_b, lower=gs_b,  info = 1:3)
# Without filtering, this shows unneeded lower bound
x
# Filter to just show bounds intended for use
x %>% filter(abs(Z) < Inf)