crt.varexplore: Variance exploration for cluster randomized trials with...

In powertools: Power and Sample Size Tools

Variance exploration for cluster randomized trials with binary outcomes

Description

This function can be used to help select a plausible value for the variance/SD of the random intercept for cluster in a cluster randomized trial with a binary outcome. Based on user-supplied values of the outcome proportions in the two arms, the function outputs, for a range of possible values of the SD of the random intercept, the intervals within which we expect about 95% of the cluster-level proportions to lie in each arm.

Usage

crt.varexplore(pc, pt, print = TRUE)

Arguments

pc	The probability of the outcome in control clusters.
pt	The probability of the outcome in treatment clusters.
print	Whether or not to print the results in a table; defaults to TRUE. To retrieve the results even when print = FALSE, assign the function output to an object.

Details

The use of this function is illustrated in Crespi CM (2025) Power and Sample Size in R.

Value

A list of the arguments and a dataframe of outputs.

Examples

crt.varexplore(pc = 0.25, pt = 0.15)
output <- crt.varexplore(pc = 0.25, pt = 0.15, print = FALSE)
output$pc

powertools documentation built on April 4, 2025, 5:02 a.m.