Power

Description

Computes the exact power for a basket trial.

Usage

pow(design, ...)

## S4 method for signature 'OneStageBasket'
pow(
design,
p1,
n,
lambda,
weight_fun,
weight_params = list(),
globalweight_fun = NULL,
globalweight_params = list(),
results = c("ewp", "group"),
...
)

## S4 method for signature 'TwoStageBasket'
pow(
design,
p1,
n,
n1,
lambda,
interim_fun,
interim_params = list(),
weight_fun,
weight_params = list(),
globalweight_fun = NULL,
globalweight_params = list(),
results = c("ewp", "group"),
...
)


Arguments

 design An object of class Basket created by setupOneStageBasket or setupTwoStageBasket. ... Further arguments. p1 Probabilities under the alternative hypothesis. If length(p1) == 1, then this is a common probability for all baskets. n The sample size per basket. lambda The posterior probability threshold. See details for more information. weight_fun Which function should be used to calculate the pairwise weights. weight_params A list of tuning parameters specific to weight_fun. globalweight_fun Which function should be used to calculate the global weights. globalweight_params A list of tuning parameters specific to globalweight_fun. results Whether only the experimentwise power (option ewp) or also the rejection probabilities per group (option group) should be returned. n1 The sample size per basket for the interim analysis in case of a two-stage design. interim_fun Which type of interim analysis should be conducted in case of a two-stage design. interim_params A list of tuning parameters specific to interim_fun.

Details

pow computes the exact experimentwise power and the exact rejection probabilities per group. The experimentwise power is the probability to reject at least one null hypothesis for a basket with p1 > p0. The rejection probabilities correspond to the type 1 error rate for baskets with p1 = p0 and to the power for baskets with p1 > p0.

If prune = TRUE then the baskets with an observed number of baskets smaller than the pooled critical value are not borrowed from. The pooled critical value is the smallest integer c for which all null hypotheses can be rejected if the number of responses is exactly c for all baskets.

This method is implemented for the class OneStageBasket.

Value

If results = "ewp" then the experimentwise power is returned as a numeric value. If results = "group" then a list with the rejection probabilities per group and the experimentwise power is returned. For baskets with p1 = p0 the rejection probabilities corresponds to the type 1 error rate, for baskets with p1 > p0 the rejection probabilities corresponds to the power.

Methods (by class)

• pow(OneStageBasket): Power for a single-stage basket design.

• pow(TwoStageBasket): Power for a two-stage basket design.

Examples

design <- setupOneStageBasket(k = 3, p0 = 0.2)
pow(design, p1 = c(0.2, 0.5, 0.5), n = 15, lambda = 0.99,
weight_fun = weights_fujikawa, weight_params = list(epsilon = 2, tau = 0))