  Named Entity Recognition (NER) is an essential precursor task for many
natural language applications, such as relation extraction or event extraction.
Much of the NER research has been done on datasets with few classes of entity
types (e.g. PER, LOC, ORG, MISC), but many real world applications (disaster
relief, complex event extraction, law enforcement) can benefit from a larger
NER typeset. More recently, datasets were created that have hundreds to
thousands of types of entities, sparking new lines of research (Sekine,
2008;Ling and Weld, 2012; Gillick et al., 2014; Choiet al., 2018). In this
paper we present a cascaded approach to labeling fine-grained NER, applying to
a newly released fine-grained NER dataset that was used in the TAC KBP 2019
evaluation (Ji et al., 2019), inspired by the fact that training data is
available for some of the coarse labels. Using a combination of transformer
networks, we show that performance can be improved by about 20 F1 absolute, as
compared with the straightforward model built on the full fine-grained types,
and show that, surprisingly, using course-labeled data in three languages leads
to an improvement in the English data.
