Template-Based Question Generation from Retrieved Sentences for Improved Unsupervised Question Answering

Code and synthetic data from our ACL 2020 paper

Abstract

Question Answering (QA) is in increasing demand as the amount of information available online and the desire for quick access to this content grows. A common approach to QA has been to fine-tune a pretrained language model on a task-specific labeled dataset. This paradigm, however, relies on scarce, and costly to obtain, large-scale human-labeled data. We propose an unsupervised approach to training QA models with generated pseudo-training data. We show that generating questions for QA training by applying a simple template on a related, retrieved sentence rather than the original context sentence improves downstream QA performance by allowing the model to learn more complex context-question relationships. Training a QA model on this data gives a relative improvement over a previous unsupervised model in F1 score on the SQuAD dataset by about 14%, and 20% when the answer is a named entity, achieving state-of-the-art performance on SQuAD for unsupervised QA.

Synthetic data

Generated synthetic data for the publication is located under enwiki_synthetic/

Requirements

1. PySpark
2. ElasticSearch 6

Instruction to generate retrieval-based synthetic data

Tokenize and perform NER:

spark-submit --master local[90] --driver-memory 200G spark_scripts/tokenize_and_ner_inputs.py --corpus=enwiki/clean/*/*.raw  --output outputs/sent-tok-rollup

Then we write the tokenized sentences to ElasticSearch index. This uses AES_HOSTS environment variable.

spark-submit --master local[90] --driver-memory 4G spark_scripts/write_sentence_level_es_index.py --corpus=outputs/sent-tok-rollup/rollup/ --es-index uqa-es-index --output outputs/write-es

Create QA synthetic dataset

spark-submit --master local[90] --driver-memory 300G spark_scripts/create_ds_synthetic_dataset.py --corpus=outputs/sent-tok-rollup/rollup/ --output outputs/synthetic-uqa-auxqs1awc1 --aux-qs=1 --aux-awc=1 --ulim-count=500000

Citation

You can cite our paper:

@inproceedings{fabbri-etal-2020-template,
    title = "Template-Based Question Generation from Retrieved Sentences for Improved Unsupervised Question Answering",
    author = "Fabbri, Alexander  and
      Ng, Patrick  and
      Wang, Zhiguo  and
      Nallapati, Ramesh  and
      Xiang, Bing",
    booktitle = "Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics",
    month = jul,
    year = "2020",
    address = "Online",
    publisher = "Association for Computational Linguistics",
    url = "https://www.aclweb.org/anthology/2020.acl-main.413",
    doi = "10.18653/v1/2020.acl-main.413",
    pages = "4508--4513",
    abstract = "Question Answering (QA) is in increasing demand as the amount of information available online and the desire for quick access to this content grows. A common approach to QA has been to fine-tune a pretrained language model on a task-specific labeled dataset. This paradigm, however, relies on scarce, and costly to obtain, large-scale human-labeled data. We propose an unsupervised approach to training QA models with generated pseudo-training data. We show that generating questions for QA training by applying a simple template on a related, retrieved sentence rather than the original context sentence improves downstream QA performance by allowing the model to learn more complex context-question relationships. Training a QA model on this data gives a relative improvement over a previous unsupervised model in F1 score on the SQuAD dataset by about 14{\%}, and 20{\%} when the answer is a named entity, achieving state-of-the-art performance on SQuAD for unsupervised QA.",
}

License

This project is licensed under the Apache-2.0 License.