Studies in the past decade on discourse parsing, such as (Ji and Eisenstein, 2014), (Feng and Hirst, 2014), and (Joty et al., 2015), greatly improved the performance of discourse parsing in general.
it has been observed that the performance across the discourse relations varies significantly (Joty et al., 2015), and that poor performance may be linked to underfitting, i.e., a lack of training data (Feng and Hirst, 2014).