psychometric (version 2.4)

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)

Value

A table with 3 elements:

LCL

lower confidence limit if CI

ICC

intra-class correlation

UCL

upper confidence limit if CI

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

Author

Thomas D. Fletcher

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)