TriggerNER: Learning with Entity Triggers as Explanations for Named Entity Recognition
This addresses the cost of annotation for NER practitioners, offering a more efficient method but is incremental as it builds on existing neural frameworks.
The paper tackles the problem of expensive human annotation for named entity recognition (NER) in new domains by introducing 'entity triggers' as explanations, achieving comparable performance with only 20% of trigger-annotated sentences versus 70% of conventional annotations.
Training neural models for named entity recognition (NER) in a new domain often requires additional human annotations (e.g., tens of thousands of labeled instances) that are usually expensive and time-consuming to collect. Thus, a crucial research question is how to obtain supervision in a cost-effective way. In this paper, we introduce "entity triggers," an effective proxy of human explanations for facilitating label-efficient learning of NER models. An entity trigger is defined as a group of words in a sentence that helps to explain why humans would recognize an entity in the sentence. We crowd-sourced 14k entity triggers for two well-studied NER datasets. Our proposed model, Trigger Matching Network, jointly learns trigger representations and soft matching module with self-attention such that can generalize to unseen sentences easily for tagging. Our framework is significantly more cost-effective than the traditional neural NER frameworks. Experiments show that using only 20% of the trigger-annotated sentences results in a comparable performance as using 70% of conventional annotated sentences.