Learning to Attend On Essential Terms: An Enhanced Retriever-Reader Model for Open-domain Question Answering
Open-domain question answering remains a challenging task as it requires models that are capable of understanding questions and answers, collecting useful information, and reasoning over evidence. Previous work typically formulates this task as a reading comprehension or entailment problem given evidence retrieved from search engines. However, existing techniques struggle to retrieve indirectly related evidence when no directly related evidence is provided, especially for complex questions where it is hard to parse precisely what the question asks. In this paper we propose a retriever-reader model that learns to attend on essential terms during the question answering process. We build (1) an essential term selector which first identifies the most important words in a question, then reformulates the query and searches for related evidence; and (2) an enhanced reader that distinguishes between essential terms and distracting words to predict the answer. We evaluate our model on multiple open-domain QA datasets where it outperforms the existing state-of-the-art, notably leading to an improvement of 8.1% on the AI2 Reasoning Challenge (ARC) dataset.
 This paper has made two major contributions: (1) a new neural reader architecture for multi-choice QA; (2) it is the first to introduce essential term selection to open-domain QA, to the best of my knowledge. The above two proposed modules (reader and selector) are not very novel, but are still valid contributions to me. Experiments on the ARC dataset shows that (1) the proposed reader itself improves over the state-of-the-art on the leaderboard; (2) introducing the essential term selector further improves the above results by about 2%. Although the paper also provides additional experiments on other datasets, I feel that the contributions of the proposed methods are not sufficiently verified. I would suggest the authors consider the following further experiments that I believe could improve its ratings: (1) The proposed reader works very well on ARC. However, besides the BiDAF, there is no comparison between the proposed reader and previous models on datasets other than ARC. In order to know whether the result generalizes or not, I think the authors should conduct experiments on the regular RACE or other multi-choice QA datasets, to fully test the reader model. (2) It is not clear whether the essential term selector could help on datasets other than science questions. Again, the authors reported results on two other datasets. However, on neither of these datasets the ET-RR was compared with ET-RR (Concat). Therefore, I have concerns that the proposed framework may only be significant on the ARC dataset. Moreover, it will be interesting to see whether the essential term selector can be learned from distant supervision. For example, using REINFORCE to learn the selector model with the rewards from the end-task performance. The current framework heavily relies on the supervised training data from (Khashabi et al., 2017), which may limit its usage to other datasets.
You are a member of the scientific community tasked with peer review. Review the following paper title and abstract.
### Title + Abstract
Learning to Attend On Essential Terms: An Enhanced Retriever-Reader Model for Open-domain Question Answering
Open-domain question answering remains a challenging task as it requires models that are capable of understanding questions and answers, collecting useful information, and reasoning over evidence. Previous work typically formulates this task as a reading comprehension or entailment problem given evidence retrieved from search engines. However, existing techniques struggle to retrieve indirectly related evidence when no directly related evidence is provided, especially for complex questions where it is hard to parse precisely what the question asks. In this paper we propose a retriever-reader model that learns to attend on essential terms during the question answering process. We build (1) an essential term selector which first identifies the most important words in a question, then reformulates the query and searches for related evidence; and (2) an enhanced reader that distinguishes between essential terms and distracting words to predict the answer. We evaluate our model on multiple open-domain QA datasets where it outperforms the existing state-of-the-art, notably leading to an improvement of 8.1% on the AI2 Reasoning Challenge (ARC) dataset.
user
<think>Okay, to do a decent peer review, I should start with summarizing what the work is about. This includes novelty, contributions, clarity, and impact. I might include suggestions to issues that I find critical to the usefulness of the work. Starting with novelty, there are different types of novelty. The first aspect of novelty is scope and scale. Is the work covering a broader perspective than previous works? The second aspect is methodology. Is the proposed methodology novel compared to previous methods? Do they provide any significant advantage over previous methodologies? The third aspect is results. Are the results different compared previous work? Does this lead to any novel theories or an extension of current theories? Next is clarity, I will be reading the work in depth and analyze if any sentences can be potentially ambiguous or misleading. If any sentences are ambiguous, I will state them and give a suggestion on how to rephrase such sentence or how to make more clear to the audience. Lastly, impact is important. I will attempt to predict how such work will impact the scientific community. This might include the applications of such work and how the work might transform the way we study a certain topic. Finally, I will might only mention issues that are critical. This is to keep the review as concise and helpful as possible.</think>



 This paper has made two major contributions: (1) a new neural reader architecture for multi-choice QA; (2) it is the first to introduce essential term selection to open-domain QA, to the best of my knowledge. The above two proposed modules (reader and selector) are not very novel, but are still valid contributions to me. Experiments on the ARC dataset shows that (1) the proposed reader itself improves over the state-of-the-art on the leaderboard; (2) introducing the essential term selector further improves the above results by about 2%. Although the paper also provides additional experiments on other datasets, I feel that the contributions of the proposed methods are not sufficiently verified. I would suggest the authors consider the following further experiments that I believe could improve its ratings: (1) The proposed reader works very well on ARC. However, besides the BiDAF, there is no comparison between the proposed reader and previous models on datasets other than ARC. In order to know whether the result generalizes or not, I think the authors should conduct experiments on the regular RACE or other multi-choice QA datasets, to fully test the reader model. (2) It is not clear whether the essential term selector could help on datasets other than science questions. Again, the authors reported results on two other datasets. However, on neither of these datasets the ET-RR was compared with ET-RR (Concat). Therefore, I have concerns that the proposed framework may only be significant on the ARC dataset. Moreover, it will be interesting to see whether the essential term selector can be learned from distant supervision. For example, using REINFORCE to learn the selector model with the rewards from the end-task performance. The current framework heavily relies on the supervised training data from (Khashabi et al., 2017), which may limit its usage to other datasets.
assistant
 This paper has made two major contributions: (1) a new neural reader architecture for multi-choice QA; (2) it is the first to introduce essential term selection to open-domain QA, to the best of my knowledge. The above two proposed modules (reader and selector) are not very novel, but are still valid contributions to me. Experiments on the ARC dataset shows that (1) the proposed reader itself improves over the state-of-the-art on the leaderboard; (2) introducing the essential term selector further improves the above results by about 2%. Although the paper also provides additional experiments on other datasets, I feel that the contributions of the proposed methods are not sufficiently verified. I would suggest the authors consider the following further experiments that I believe could improve its ratings: (1) The proposed reader works very well on ARC. However, besides the BiDAF, there is no comparison between the proposed reader and previous models on datasets other than ARC. In order to know whether the result generalizes or not, I think the authors should conduct experiments on the regular RACE or other multi-choice QA datasets, to fully test the reader model. (2) It is not clear whether the essential term selector could help on datasets other than science questions. Again, the authors reported results on two other datasets. However, on neither of these datasets the ET-RR was compared with ET-RR (Concat). Therefore, I have concerns that the proposed framework may only be significant on the ARC dataset. Moreover, it will be interesting to see whether the essential term selector can be learned from distant supervision. For example, using REINFORCE to learn the selector model with the rewards from the end-task performance. The current framework heavily relies on the supervised training data from (Khashabi et al., 2017), which may limit its usage to other datasets.