The annotation of the Central Unit in Rhetorical Structure Trees: A Key Step in Annotating Rhetorical Relations

This article aims to analyze how agreement regarding the central unit (macrostructure) influences agreement when establishing rhetorical relations (microstructure). To do so, the authors conducted an empirical study of abstracts from research articles in three domains (medicine, terminology, and science) in the framework of Rhetorical Structure Theory (RST). The results help to establish a new criteria to be used in RST-based annotation methodology of rhetorical relations. Furthermore, a set of verbs which can be utilized to detect the central unit of abstracts was identified and analyzed with the aim of designing a preliminary study of an automatic system for identifying the central unit in rhetorical structures.