A Comparative Study of Syntactic Parsers for Event Extraction

The extraction of bio-molecular events from text is an important task for a number of domain applications such as pathway construction. Several syntactic parsers have been used in Biomedical Natural Language Processing (BioNLP) applications, and the BioNLP 2009 Shared Task results suggest that incorporation of syntactic analysis is important to achieving state-of-the-art performance. Direct comparison of parsers is complicated by to differences in the such as the division between phrase structureand dependencybased analyses and the variety of output formats, structures and representations applied. In this paper, we present a taskoriented comparison of five parsers, measuring their contribution to bio-molecular event extraction using a state-of-the-art event extraction system. The results show that the parsers with domain models using dependency formats provide very similar performance, and that an ensemble of different parsers in different formats can improve the event extraction system.