For example, the best question classifier QC3 outperforms the worst one (QC1) by 1.5%, 2.0%, and 2.0% MRR scores for NE, NE-4 and REG respectively.
it is surprising that the MRR and top5 contribution of NE and NE-4 decreases if QC1 is replaced by QC2, although the top1 score results in performance gain slightly.