Investigating the role of Named Entity Recognition in Question Answering Models

Machine Reading Comprehension (MRC) is a challenging Question - Answering (QA) task that helps the user in providing the answer to the given question. There is a lot of progress in this area due to the availability of large datasets and large pre-trained language models based on transformer architecture (BERT). Named Entity Recognition (NER) was used for neural QA systems to improve performance. However, whether NER plays a vital role in a QA system built using contextual embeddings obtained through BERT variants is not explored. To fill this gap, we investigate whether NER is helpful in improving the performance of QA systems built using BERT variants. We experimented with Squad 2.0 using SpanBERT. The Squad 2.0 dataset has both answerable and unanswerable questions. The proposed model finds the answer span if the question is answerable and, provides justification for the unanswerable questions. We perform question analysis to find the expected answer tag and then use that information to find the relevant parts of the passage in order to retrieve the answer span.