In this section, we investigate the effectiveness of NCEL in the "easy" and "hard" datasets, respectively.
tAC2010, which has two mentions per document on average (Section 5.1) and high prior probabilities of correct candidates (Figure 3), is regarded as the "easy" case for EL, and WW is the "hard" case since it has the most mentions with balanced prior probabilities (Guo and Barbosa, 2017).