irr (version 0.84)

kendall: Kendall's coefficient of concordance W

Description

Computes Kendall's coefficient of concordance as an index of interrater reliability of ordinal data. The coefficient could be corrected for ties within raters.

Usage

kendall(ratings, correct = FALSE)

Arguments

ratings

n*m matrix or dataframe, n subjects m raters.

correct

a logical indicating whether the coefficient should be corrected for ties within raters.

Value

A list with class '"irrlist"' containing the following components:

$method

a character string describing the method applied for the computation of interrater reliability.

$subjects

the number of subjects examined.

$raters

the number of raters.

$irr.name

a character string specifying the name of the coefficient.

$value

coefficient of interrater reliability.

$stat.name

a character string specifying the name and the df of the corresponding chi-squared test.

$statistic

the value of the test statistic.

$p.value

the p-value for the test.

$error

the character string of a warning message if ties were found within raters.

Details

Missing data are omitted in a listwise way. Kendall's W should be corrected for ties if raters did not use a true ranking order for the subjects. A test for the significance of Kendall's W is only valid for large samples.

References

Kendall, M.G. (1948). Rank correlation methods. London: Griffin.

See Also

cor, meanrho

Examples

# NOT RUN {
data(anxiety)
kendall(anxiety, TRUE)
# }