iccmult

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The goal of iccmult is to estimate the intracluster correlation coefficient (ICC) of clustered categorical response data. It provides two estimation methods, a resampling based estimator and the method of moments estimator. These are obtained by specifying a method in the function iccmulti::iccmult(). This package also includes a function to generate simulated clustered categorical response data: iccmulti::rccat().

Installation

You can install iccmult from within R or RStudio with:

install.packages("iccmult")

Alternatively, install the package from GitHub with:

# install.packages("pak")
pak::pak("ncs14/iccmult")

Example

This is a basic example which shows you how to generate clustered categorical response data. The response probabilities must sum 1 and the desired ICC must be a value between 0 and 1. The number of clusters is set to 20 and each cluster is of size 25. The output of rccat is a two column data frame of a cluster identifier and a categorical response vector.

library(iccmult)
clustdat3 <- rccat(rho=0.25, prop=c(0.2,0.3,0.5), noc=20, csize=25)

The iccmulti() function is called as follows to estimate the ICC on the resulting data frame. The function expects two variables: a cluster identifier and the categorical response vector. The call below requests both the resampling and the moments estimates.

iccclust <- iccmulti(cid, y, clustdat3, method=c("rm","mom"))

The result is a list of length two, each component holding the estimated ICC, se(ICC), and confidence interval bounds from each estimation method.