We present a noun phrase coreference system that extends the work of Soon et al. (2001) and, to our knowledge, produces the best results to date on the MUC-6 and MUC-7 coreference resolution data sets -F-measures of 70.4 and 63.4, respectively. Improvements arise from two sources: extra-linguistic changes to the learning framework and a large-scale expansion of the feature set to include more sophisticated linguistic knowledge.

While automatic keyphrase extraction has been examined extensively, state-of-theart performance on this task is still much lower than that on many core natural language processing tasks. We present a survey of the state of the art in automatic keyphrase extraction, examining the major sources of errors made by existing systems and discussing the challenges ahead.

We present a supervised learning approach to identification of anaphoric and non-anaphoric noun phrases and show how such information can be incorporated into a coreference resolution system. The resulting system outperforms the best MUC-6 and MUC-7 coreference resolution systems on the corresponding MUC coreference data sets, obtaining F-measures of 66.2 and 64.0, respectively.

While recent years have seen a surge of interest in automated essay grading, including work on grading essays with respect to particular dimensions such as prompt adherence, coherence, and technical quality, there has been relatively little work on grading the essay dimension of argument strength, which is arguably the most important aspect of argumentative essays. We introduce a new corpus of argumentative student essays annotated with argument strength scores and propose a supervised, feature-rich approach to automatically scoring the essays along this dimension. Our approach significantly outperforms a baseline that relies solely on heuristically applied sentence argument function labels by up to 16.1%.

Essay stance classification, the task of determining how much an essay's author agrees with a given proposition, is an important yet under-investigated subtask in understanding an argumentative essay's overall content. We introduce a new corpus of argumentative student essays annotated with stance information and propose a computational model for automatically predicting essay stance. In an evaluation on 826 essays, our approach significantly outperforms four baselines, one of which relies on features previously developed specifically for stance classification in student essays, yielding relative error reductions of at least 11.3% and 5.3%, in micro and macro F-score, respectively. 1 Previous approaches to stance classification have focused on three discussion/debate settings, namely congressional floor debates (