Looking into POS diversity and parser label diversity as shown in  Table 4: Accuracy from 10-folds cross validation using all features diversity; 0.37 for syntax labels diversity).
our work also complements prior knowledge gained from studies that predict reviewer expertise based on personal ratings (Amblee & Bui, 2007;Flanagin & Metzger, 2013;Plucker et al., 2009), and/or the online behaviour of reviewers (Liu et al., 2008).