In this case, the evidence shows that the proposed index is extremely robust to changes in these parameters. When all k values between 10% and 70% were considered, 93% of all possible comparisons between pairs of observations were robust.3 When k values were restricted to a range of between 20% and 40%, the percentage of robust comparisons rose to 98%. The Kendall coefficient for k values between 10% and 70% varies between 0.89 and 0.99, while the Spearman coefficient ranges between 0.98 and 0.99.