HAS-QA: Hierarchical Answer Spans Model for Open-domain Question Answering

Understand

This paper is concerned with open-domain question answering (i.e., OpenQA).

• Recently, some works have viewed this problem as a reading comprehension (RC) task, and directly applied successful RC models to it.
• However, the performances of such models are not so good as that in the RC task.
• In our opinion, the perspective of RC ignores three characteristics in OpenQA task: 1) many paragraphs without the answer span are included in the data collection; 2) multiple answer spans may exist within one given paragraph; 3) the end position of an answer span is dependent with the start position.