The Kappa coefficient is a statistical measure of inter-rater agreement for qualitative (categorical) items. Measure developers can think of Cohen’s kappa as a chance-corrected proportional agreement. Possible values range from +1 (perfect agreement), 0 (no agreement above that expected by chance) to -1 (complete disagreement).

# Glossary

Kappa Coefficient

Kappa Coefficient

Kendall's Tau

Kendall's Tau

Kendall’s Tau is a statistic used to measure the ordinal association between two measured quantities. It is a measure of rank correlation: the similarity of the orderings of the data when ranked by each of the quantities.

Comprehensive R Archive Network. (n.d.). Kendall's Ƭa. Tools for Descriptive Statistics. Retrieved November 13, 2023, from

https://search.r-project.org/CRAN/refmans/DescTools/html/KendallTauA.html

Kruskal-Wallis test

Kruskal-Wallis test

A Kruskal-Wallis test is a nonparametric method for comparing the means among more than two samples. The null hypothesis of the Kruskal-Wallis test is the mean ranks of the groups are the same. The test does not assume a normal distribution of the underlying data.

Kuder-Richardson Formula 20

Kuder-Richardson Formula 20

The Kuder-Richardson Formula 20 (KR-20) is a quantitative measure of internal consistency reliability for measurements with binary variables.