Most recent work uses a single human judgment to capture all linguistic qualities of the summary (Hsu et al., 2018; Kryściński et al., 2018;<cite> Narayan et al., 2018b</cite>; Song et al., 2018; Guo et al., 2018) ; we group them under "Fluency" in Table 1 with an exception of "Clarity" which was evaluated in the DUC evaluation campaigns (Dang, 2005) .