I try to calculate the Kendall tau-b rank correlation for a huge number of paired sets. Some of those sets contain only ties, e.g.,
x1 = [1,1,1,1,1,1]
which is compared to another set
x2 = [1,1,1,1,2,2]
Python's Kendall tau-b module
import scipy.stats as stats stats.kendalltau(x1, x2)
I guess this is because one of the factors in the denominator is zero. Is there any solution to get an approximate tau-b coefficient for such situations. Does anybody know what the limit would be? Or which value one usually would assign in such situations?