surv1sel: Compute selection probabilities in a randomized phase II...

In raredd/desmon: Functions for design and monitoring of clinical trials

Compute selection probabilities in a randomized phase II study with a failure time endpoint

Description

Uses simulations with exponential failure times and uniform accrual to estimate the probability of each arm being the best in a randomized phase II study, where best is defined as the lowest hazard rate in a Cox proportional hazards model.

Usage

surv1sel(ng, npg, acc.per, nevents, haz, nsamp = 1000)

Arguments

ng	Number of groups
npg	Number of subjects per group (the same scalar value is assumed for all groups)
acc.per	The planned accrual period
nevents	The total planned number of events (across all arms) at the time of analysis
haz	A vector of length ng giving the failure hazard rates for the expoential distribution in each group
nsamp	The number of samples to generate

Details

Assumes that the clinical trial will enroll ng*npg subjects uniformly over the period (0,acc.per), with the analysis performed when nevents failures have been observed. A Cox proportional hazards model with indicator variables for the groups is fit and the group estimated to have the lowest hazard rate is selected as the best. In the function, samples are repeatedly generated from exponential distributions with the specified hazard rates and the proportion of the samples for which each group is selected as the best is calculated.

Value

The vector giving the proportion of times each group is selected as the best (ie has the lowest estimated hazard rate).

See Also

surv1samp

Examples

surv1sel(6, 55, 12, 40 * 6, log(2) / c(7.2, 4.8, 4.8, 4.8, 4.8, 4.8))

raredd/desmon documentation built on May 7, 2024, 3:46 p.m.