Dealing with Ties in Rank Correlation

In the field of Information Retrieval (IR), rankings of systems evaluated under different conditions are often compared to each other. This measure of correspondence between rankings, termed as rank correlation, must accurately capture the scenario for which the correlation is computed. Very often, these rankings may have tied systems, for which...

The Treatment of Ties in AP Correlation

The Kendall tau and AP correlation coefficients are very commonly use to compare two rankings over the same set of items. Even though Kendall tau was originally defined assuming that there are no ties in the rankings, two alternative versions were soon developed to account for ties in two different scenarios: measure the accuracy of an...