Indicates the degree of association of ordinal assessments made by multiple appraisers when evaluating the same samples. Kendall's coefficient is commonly used in attribute agreement analysis (attribute gage R&R).
For example, chicken wings are rated on a 1-10 scale. The consequences of misclassifying a suicide hot wing (10) as medium (5) are more serious than misclassifying it as intensely hot (8).
Kendall's values range from 0 to +1. The higher the value of Kendall's, the stronger the association. Generally Kendall's coefficients of 0.9 or above are considered very good. A high or significant Kendall's coefficient means that the appraisers are applying essentially the same standard when evaluating the samples.
Kendall's correlation coefficient
If you provide a known rating for each sample, Minitab also calculates Kendall's correlation coefficients. The correlation coefficients are given for each appraiser to indicate the agreement of each appraiser with the known standard; and an overall coefficient to represent all appraisers with the standards. The correlation coefficient helps you determine whether an appraiser is consistent but inaccurate.