---
title: "ContractNLI: A Dataset for Document-level — Koreeda 2021"
description: "Contract review is slow and expensive, and people who cannot afford lawyers often sign agreements without expert checking."
authors: ["Yuta Koreeda", "Christopher Manning"]
year: 2021
venue: "Findings of the Association for Computational Linguistics: EMNLP 2021"
source: "https://aclanthology.org/2021.findings-emnlp.164/"
doi: "10.18653/v1/2021.findings-emnlp.164"
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/koreeda-2021-contractnli-dataset-document-level-natural/"
---
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# ContractNLI: A Dataset for Document-level Natural Language Inference for Contracts

**Authors:** Yuta Koreeda, [Christopher Manning](https://md.research.elamur.ai/free/en/authors/christopher-manning/) · **Year:** 2021 · **Venue:** Findings of the Association for Computational Linguistics: EMNLP 2021 · **Licence:** [CC BY 4.0 (ACL Anthology)](https://creativecommons.org/licenses/by/4.0/)

**Links:** [Publisher's page](https://aclanthology.org/2021.findings-emnlp.164/) · [PDF](https://aclanthology.org/2021.findings-emnlp.164.pdf) · [DOI 10.18653/v1/2021.findings-emnlp.164](https://doi.org/10.18653/v1/2021.findings-emnlp.164) · [OpenAlex](https://openalex.org/W3201977280)

**Citations:** 76 citations (openalex-snapshot · 2026-10-14) · [101](#cited-by) in our library, of the 140884 papers whose bibliographies we read

## Summary
Contract review is slow and expensive, and people who cannot afford lawyers often sign agreements without expert checking. This paper treats contract analysis as document-level natural language inference (NLI). Given a whole contract and a fixed list of hypotheses, a system must label each hypothesis as entailed, contradicted or not mentioned. It must also point to the supporting evidence, with each evidence unit being either a single sentence or one item from a list.

The authors built ContractNLI, a corpus of 607 non-disclosure agreements (NDAs) collected from EDGAR and web search, converted to clean text and annotated against 17 hypotheses. Most documents far exceed BERT's input limit, and token-level answer extraction suits this task poorly. The authors therefore propose Span NLI BERT, which classifies marked spans with multiple labels and splits long contexts more carefully.

Span NLI BERT clearly outperforms existing Transformer baselines. Still, the NLI decision proves harder than finding evidence, and rare labels and clauses negated by exceptions remain weak points. The work offers a realistic legal benchmark for reasoning over long documents.

## Key points
- ContractNLI contains 607 annotated NDAs, which the authors describe as the largest annotated contract corpus at the time. It is split 70:10:20 into train, development and test sets (423 / 61 / 123), stratified by source format (plain text, HTML, PDF).
- Each contract is judged against the same 17 hypotheses, such as survival of obligations or no reverse engineering. Labels are ENTAILMENT, CONTRADICTION and NOT MENTIONED, and evidence spans are marked only for the first two.
- Training documents average about 2,254 tokens and 77.8 candidate spans. About 86% are longer than BERT's 512-token limit.
- Span NLI BERT predicts evidence through multi-label classification over span markers instead of start/end tokens. With BERT base it even beats SQuAD-style BERT large.
- Text was extracted with the authors' own PDF tool and segmented with Stanza. Annotation ran on Amazon Mechanical Turk at an average pay of 18.31 USD per hour.

*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

101 papers of our library cite it (of the 140884 whose bibliographies we read); 4 of them have a page here, 97 not yet.

- [LCHAIM - Investigating Long Context Reasoning in Hebrew](https://md.research.elamur.ai/free/en/papers/findings-2025-malul-lchaim-investigating-long-context-reasoning/)
- [LegalBench: A Collaboratively Built Benchmark for Measuring Legal Reasoning in Large Language Models](https://md.research.elamur.ai/free/en/papers/guha-2023-legalbench-collaboratively-built-benchmark-measuring/)
- [SCROLLS: Standardized CompaRison Over Long Language Sequences](https://md.research.elamur.ai/free/en/papers/shaham-2022-scrolls-standardized-comparison-over-long/)
- [UL2: Unifying Language Learning Paradigms](https://md.research.elamur.ai/free/en/papers/tay-2022-ul2-unifying-language-learning-paradigms/)

## Cite

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

```bibtex
@inproceedings{koreeda2021contractnli,
  title = {{ContractNLI: A Dataset for Document-level Natural Language Inference for Contracts}},
  author = {Koreeda, Yuta and Manning, Christopher},
  booktitle = {Findings of the Association for Computational Linguistics: EMNLP 2021},
  year = {2021},
  doi = {10.18653/v1/2021.findings-emnlp.164},
  url = {https://doi.org/10.18653/v1/2021.findings-emnlp.164}
}
```

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- [↑ back to papers of 2021](https://md.research.elamur.ai/free/en/papers/2021/page/2/)

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