KendallW: 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

KendallW(x, correct = FALSE, test = FALSE, na.rm = FALSE)

Arguments

$k x m$ matrix or dataframe, k subjects (in rows) m raters (in columns).

correct

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

test

a logical indicating whether the test statistic and p-value should be reported.

na.rm

logical, indicating whether NA values should be stripped before the computation proceeds. If set to TRUE only the complete cases of the ratings will be used. Defaults to FALSE.

Value

Either a single value if test is set to FALSE or elsea list with class “htest” containing the following components:

Details

Kendall's W should be corrected for ties, if raters did not use a true ranking order for the subjects. The test for the significance of Kendall's W is only valid for large samples.

References

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

Examples

Run this code

anxiety <- data.frame(rater1=c(3,3,3,4,5,5,2,3,5,2,2,6,1,5,2,2,1,2,4,3),
                      rater2=c(3,6,4,6,2,4,2,4,3,3,2,3,3,3,2,2,1,3,3,4),
                      rater3=c(2,1,4,4,3,2,1,6,1,1,1,2,3,3,1,1,3,3,2,2))

KendallW(anxiety, TRUE)

# with test results
KendallW(anxiety, TRUE, test=TRUE)

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