---
title: "Synthetic QA Corpora Generation with — Alberti 2019"
description: "This paper asks whether QA systems can benefit from a pretraining task closer to question answering than masked language modeling."
authors: ["Chris Alberti", "Daniel Andor", "Emily Pitler", "Jacob Devlin", "Michael Collins"]
year: 2019
venue: "Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics"
source: "https://aclanthology.org/P19-1620/"
doi: "10.18653/v1/p19-1620"
licence: "CC BY 4.0 (ACL Anthology)"
licence_url: "https://creativecommons.org/licenses/by/4.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/en/papers/alberti-2019-synthetic-qa-corpora-generation-roundtrip/"
---
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# Synthetic QA Corpora Generation with Roundtrip Consistency

**Authors:** [Chris Alberti](https://md.research.elamur.ai/free/en/authors/chris-alberti/), [Daniel Andor](https://md.research.elamur.ai/free/en/authors/daniel-andor/), [Emily Pitler](https://md.research.elamur.ai/free/en/authors/emily-pitler/), [Jacob Devlin](https://md.research.elamur.ai/free/en/authors/jacob-devlin/), [Michael Collins](https://md.research.elamur.ai/free/en/authors/michael-collins/) · **Year:** 2019 · **Venue:** Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics · **Licence:** [CC BY 4.0 (ACL Anthology)](https://creativecommons.org/licenses/by/4.0/)

**Links:** [Publisher's page](https://aclanthology.org/P19-1620/) · [PDF](https://aclanthology.org/P19-1620.pdf) · [DOI 10.18653/v1/p19-1620](https://doi.org/10.18653/v1/p19-1620) · [OpenAlex](https://openalex.org/W2949849869)

**Citations:** 209 citations (openalex-snapshot · 2026-10-14) · [146](#cited-by) in our library, of the 140673 papers whose bibliographies we read

## Summary
This paper asks whether QA systems can benefit from a pretraining task closer to question answering than masked language modeling. The authors build millions of synthetic question–answer–context triples from unlabeled Wikipedia text using three BERT-based models trained on labeled data. The first picks a candidate answer span from a passage. The second writes a question about that span. The third answers the generated question. A triple is kept only when the predicted answer agrees with the original span, a filter they call roundtrip consistency, inspired by back-translation in MT. A QA model is first pretrained on this synthetic corpus and then fine-tuned on SQuAD2 or NQ.

There are two variants. One only fine-tunes public BERT, so it is fully reproducible. The other uses a fully pretrained sequence-to-sequence Transformer for question generation. Both improve results. NQ reaches a new state of the art, and the strongest SQuAD2 ensemble nearly matches human scores. The work shows that cheap, filtered synthetic data can serve as an effective QA-specific pretraining signal.

## Key points
- **Data sources:** 8M unlabeled 512-token windows from the NQ training text (about 1B words). After roundtrip filtering, these yielded 2.4M SQuAD2-style and 3.2M NQ-style answerable examples. Added unanswerable examples brought the totals to 3M and 4M.
- **Fine-tuning-only setting on SQuAD2:** BERT-Large rose from 78.7/81.9 to 81.2/84.0 dev EM/F1 when pretrained on combined SQuAD2+NQ synthetic data.
- **Full pretraining setting:** a 50M-example synthetic corpus plus a 6-model ensemble scored 86.7 EM / 89.1 F1 on the SQuAD2 test set. Human performance is 86.8 / 89.5, and the system ranked third on the leaderboard (May 2019).
- **NQ results:** over the BERT joint baseline, short-answer test F1 rose from 52.1 to 53.9 and long-answer test F1 from 66.2 to 66.8.
- **Value of the filter:** in a manual check, 39% of kept triples were correct versus 16% of discarded ones. Filtered data consistently beat unfiltered data in the learning curves.

*Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.*

Fields: [Natural language processing](https://md.research.elamur.ai/free/en/shelves/nlp/)

## Cited by

Cited by

146 papers of our library cite it (of the 140673 whose bibliographies we read); 3 of them have a page here, 143 not yet.

- [Promptagator: Few-shot Dense Retrieval From 8 Examples](https://md.research.elamur.ai/free/en/papers/dai-2022-promptagator-few-shot-dense-retrieval/)
- [MLQA: Evaluating Cross-lingual Extractive Question Answering](https://md.research.elamur.ai/free/en/papers/lewis-2019-mlqa-evaluating-cross-lingual-extractive/)
- [PAQ: 65 Million Probably-Asked Questions and What You Can Do With Them](https://md.research.elamur.ai/free/en/papers/lewis-2021-paq-65-million-probably-asked/)

## Cite

The paper itself, not this page. BibTeX from the library's record of the work.

```bibtex
@inproceedings{alberti2019synthetic,
  title = {{Synthetic QA Corpora Generation with Roundtrip Consistency}},
  author = {Alberti, Chris and Andor, Daniel and Pitler, Emily and Devlin, Jacob and Collins, Michael},
  booktitle = {Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics},
  year = {2019},
  doi = {10.18653/v1/p19-1620},
  url = {https://doi.org/10.18653/v1/p19-1620}
}
```

- [← previous SuperGLUE: A Stickier Benchmark for General-Purpose Language Understanding Systems](https://md.research.elamur.ai/free/en/papers/wang-2019-superglue-stickier-benchmark-general-purpose/)
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## References

12 references, 4 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet.

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