stoppingrule (version 0.6)

OC.rule.bin: Operating Characteristics Function (Binary Data)

Description

Compute operating characteristics for a stopping rule at a set of toxicity rates. Characteristics calculated include the overall rejection probability, the expected number of patients evaluated, and the expected number of events.

Usage

OC.rule.bin(rule, ps, tau = NULL, A = NULL)

Value

A matrix with columns containing the toxicity probabilities ps, the corresponding rejection probabilities, and the corresponding expected number of events. If tau and A are also specified, the expected numbers of enrolled patients and the expected calendar time at the point of stopping/study end are also included.

Arguments

rule

A rule.bin object calculated by calc.rule.bin() function

ps

A vector of toxicity probabilities at which the operating characteristics will be computed

tau

Length of observation period

A

Length of the enrollment period

Details

If tau and A are specified, the expected number of events includes events among patients who are still pending evaluation at the time of early stopping, computed under an assumption of a random uniform accrual distribution. Otherwise, only events that occurred prior to stopping are included, as the number of events occurring in pending patients depends on tau and A.

Examples

if (FALSE) # Binomial Pocock test in 50 patient cohort at 10% level, expected toxicity probability of 20%
poc_rule = calc.rule.bin(ns=1:50,p0=0.20,alpha=0.10,type="Pocock")

# Bayesian beta-binomial method of Geller et al. in 50 patient cohort at 10% level,
# expected toxicity probability of 20%
bb_rule = calc.rule.bin(ns=1:50,p0=0.20,alpha=0.10,type="BB",param=c(2,8))

# Compute operating characteristics at toxicity probabilities of 20%, 25%, 30%, 35%, and 40%
OC.rule.bin(rule=poc_rule,ps=seq(0.2,0.4,0.05))
OC.rule.bin(rule=bb_rule,ps=seq(0.2,0.4,0.05),tau=30,A=730)