As a benchmark, we will use the results of the systems by Burckhardt et al. BIBREF22 , Liu et al. BIBREF18 , Dernoncourt et al. BIBREF9 and Yang et al. BIBREF10 on the i2b2 dataset and the performance of Burckhardt et al. on the nursing corpus. 
 Question: What is their baseline?
Burckhardt et al. BIBREF22 Liu et al. BIBREF18 Dernoncourt et al. BIBREF9 Yang et al. BIBREF10