psychometric (version 2.2)

ICC.CI: Confidence interval for the Intra-class Correlation

Description

Computes the CI at the desired level for the ICC1 and ICC2

Usage

ICC1.CI(dv, iv, data, level = 0.95)
ICC2.CI(dv, iv, data, level = 0.95)

Arguments

dv

The dependent variable of interest

iv

cluster or grouping variable

data

data.frame containing the data

level

Significance Level for constructing the CI, default is .95

Value

A table with 3 elements:

LCL

lower confidence limit if CI

ICC

intra-class correlation

UCL

upper confidence limit if CI

Details

Computes the ICC from a one-way ANOVA. The CI is then computed at the desired level using formulae provided by McGraw & Wong (1996). They use the terminology ICC(1) and ICC(k) for ICC1 and ICC2 respectively.

References

McGraw, K. O. & Wong, S. P. (1996). Forming some inferences about some intraclass correlation coefficients. Psychological Methods, 1, 30-46.

Bliese, P. (2000). Within-group agreement, non-independence, and reliability: Implications for data aggregation and analysis. In K. J. Klein & S. W. J. Kozlowski (Eds.), Multilevel theory, research, and methods in organizations: Foundations, extensions, and new directions (pp. 349-381). San Francisco: Jossey-Bass.

See Also

ICC.lme, ICC1, ICC2

Examples

library(multilevel)
data(bh1996)
ICC1.CI(HRS, GRP, bh1996)
ICC2.CI(HRS, GRP, bh1996)