More importantly, however, we notice that some error types achieve much higher scores than others, which suggests some annotators agree on certain categories more than others.
noun number (Nn) and subjectverb agreement (SVA) errors achieve the highest scores, at just under 90% F 0.5 , which is also not far from the 100% F 0.5 that would be achieved if we had gold standard answers for all possible alternative corrections of this type.