A Sequencing Model for Situation Entity Classification

Situation entities (SEs) are the events, states, generic statements, and embedded facts and propositions introduced to a discourse by clauses of text. We report on the first datadriven models for labeling clauses according to the type of SE they introduce. SE classification is important for discourse mode identification and for tracking the temporal progression of a discourse. We show that (a) linguistically-motivated cooccurrence features and grammatical relation information from deep syntactic analysis improve classification accuracy and (b) using a sequencing model provides improvements over assigning labels based on the utterance alone. We report on genre effects which support the analysis of discourse modes having characteristic distributions and sequences of SEs.