Predicative NPs and the annotation of reference chains

In the development of machine learning systems for identification of reference chains, hand-annotated corpora play a crucial role. This paper concerns the question of how predicative NPs should be annotated w.r.t. coreference in corpora for such systems. This question highlights the tension that sometimes appears in the development of corpora between linguistic considerations and the aim for perfection on the one hand and practical applications and the aim for efficiency on the other. Many current projects that seek to identify coreferential links automatically, assume an annotation strategy which instructs the annotator to mark a predicative NP as coreferential with its subject if it is part of a positive sentence. This paper argues that such a representation is not linguistically plausible, and that it will fail to generate an optimal result.