sample.size.NI {dani} R Documentation

## Sample size calculation tool for Non-Inferiority trials

### Description

A function for calculating sample size of a non-inferiority trial.

### Usage

sample.size.NI(p0.expected, p1.expected, p1.tolerable, sig.level=0.025, power=0.9, r=1,
scale="RD", print.out=TRUE)


### Arguments

 p0.expected Expected event risk in the control arm. p1.expected Expected event risk in the active arm. p1.tolerable Maximum tolerable active event risk for declaring non-inferiority. sig.level One-sided significance level for testing. Default is 0.025, i.e. 2.5%. power Power of the trial, i.e. one minus type-II error of the study. Default is 0.9, i.e.90%. r Allocation ratio, i.e. ratio between sample sizes in the active and control goups. Deafault is 1. scale The scale on which we define the non-inferiority trial. Can be one of "RD" (Risk difference), "RR" (log-risk ratio) or "AS" (arc-sine difference). print.out Logical. If FALSE, no output is printed.

### Details

This is a function to calculate sample size needed to test non-inferiority of an active treatment against the control within a specific NI margin. The margin can be specified on a number of different scales, which give different answers.

### Value

The output is a vector ss, containing the sample sizes for the control and active arms respectively.

### Examples


p0.expected<-0.05 # Expected control event rate
p1.expected<-p0.expected # Same as expected active event rate
p1.tolerable<-0.1  # Maximum tolerable active event rate
r<-1       # Allocation ratio
power<-0.9 # Power
alph<-0.025 # Significance level

sample.size.RD<-sample.size.NI(sig.level=alph, power=power,
p0.expected=p0.expected, p1.expected=p1.expected,
p1.tolerable=p1.tolerable, r=r)  # Risk difference scale
sample.size.lRR<-sample.size.NI(sig.level=alph, power=power,
p0.expected=p0.expected, p1.expected=p1.expected,
p1.tolerable=p1.tolerable, r=r, scale="RR")  # Log-risk ratio scale
sample.size.AS<-sample.size.NI(sig.level=alph, power=power,
p0.expected=p0.expected, p1.expected=p1.expected,
p1.tolerable=p1.tolerable, r=r, scale="AS")  # Arc-sine difference scale



[Package dani version 0.1-1 Index]