A Unified Local and Global Model for Discourse Coherence

Abstract

NOTE TO READERS: We have recently detected a software bug which affects the results of our standalone entity grid experiments. (The bug was in our syntactic analysis code, which incorrectly failed to label the second object of a conjoint VP; in the phrase “wash the dishes and clean the sink”, ‘dishes ’ would be correctly labeled as O but ‘sink ’ mislabeled as X.) This bug happened to have an unfortunate interaction with the ”This is preliminary information ” preamble mentioned in section 5. The results in table 2 above the line are incorrect; our relaxed entity grid does not outperform the naive grid on the discriminative test. This implies that our argument motivating the relaxed model at the end of section 2 is misguided. The design and performance of the joint model is unaffected. We present a model for discourse coherence which combines the local entitybased approach of (Barzilay and Lapata, 2005) and the HMM-based content model