---
title: "Learning Noun Phrase Anaphoricity to Improve — Ng 2004"
description: "In principle, a coreference system could skip noun phrases that are not anaphoric."
authors: ["Vincent Ng"]
year: 2004
venue: "Proceedings of the 42nd Annual Meeting of the Association for Computational Linguistics (ACL-04)"
source: "https://aclanthology.org/P04-1020/"
doi: "10.3115/1218955.1218975"
licence: "CC BY-NC-SA 3.0 (ACL Anthology, before 2016)"
licence_url: "https://creativecommons.org/licenses/by-nc-sa/3.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/papers/ng-2004-learning-noun-phrase-anaphoricity-improve/"
---
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# Learning Noun Phrase Anaphoricity to Improve Conference Resolution: Issues in Representation and Optimization

**Authors:** [Vincent Ng](https://md.research.elamur.ai/free/authors/vincent-ng/) · **Year:** 2004 · **Venue:** Proceedings of the 42nd Annual Meeting of the Association for Computational Linguistics (ACL-04) · **Licence:** [CC BY-NC-SA 3.0 (ACL Anthology, before 2016)](https://creativecommons.org/licenses/by-nc-sa/3.0/)

**Links:** [Publisher's page](https://aclanthology.org/P04-1020/) · [PDF](https://aclanthology.org/P04-1020.pdf) · [DOI 10.3115/1218955.1218975](https://doi.org/10.3115/1218955.1218975) · [OpenAlex](https://openalex.org/W2171828761)

**Citations:** 62 citations (openalex-snapshot · 2026-10-14) · [10](#cited-by) in our library, of the 140673 papers whose bibliographies we read

## Summary
In principle, a coreference system could skip noun phrases that are not anaphoric. However, earlier attempts to add automatically predicted anaphoricity to such systems often lowered performance. Ng studies two design choices that had received little attention. The first is representation: anaphoricity can act as a hard filter (constraint-based) or as one more feature for the coreference learner. The second is optimization: the anaphoricity classifier can be tuned on its own (local) or tuned for end coreference performance (global). For global optimization, he proposes a conservativeness-based anaphoricity model with a single tunable parameter, chosen on held-out development data. That parameter is either a misclassification cost ratio (RIPPER) or a probability threshold (MaxEnt). He tests all four combinations on the three ACE data sets, using both RIPPER and MaxEnt as coreference learners. The constraint-based, globally optimized variant (CBGO) works best. It beats a no-anaphoricity baseline and the usual locally optimized filter without needing extra labeled data. This shows that anaphoricity filtering pays off only when it is tuned to the downstream task.

## Key points
- **Data and learners:** The experiments use the ACE data sets BNEWS, NPAPER and NWIRE. Coreference follows the classification-plus-clustering framework of Soon et al. (2001) and Ng and Cardie (2002b).
- **Tuning the filter:** Local optimization uses default settings (cost ratio cr = 1, threshold t = 0.5). The globally tuned values were always more conservative, which means the default filters label too many NPs as non-anaphoric.
- **Precision–recall trade-off:** On NPAPER development data with RIPPER/RIPPER, raising cr increases recall and lowers precision. F-measure peaks at cr = 4.
- **Feature-based variant:** The feature-based global variant (FBGO) did worse than CBGO in 11 of 12 settings. It significantly improved the baseline only four times and was no better than the local approaches.
- **Most informative features:** By information gain, the strongest anaphoricity features are HEAD MATCH, STR MATCH and PRONOUN. PROPER NOUN, BARE SINGULAR/BARE PLURAL and ARTICLE features, which reflect definiteness, also carry substantial information.

*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: [Linguistics & languages](https://md.research.elamur.ai/free/shelves/linguistics/)

Topics: [Coreference resolution](https://md.research.elamur.ai/free/topics/coreference-resolution/)

## Cited by

Cited by

10 papers of our library cite it (of the 140673 whose bibliographies we read); 8 of them have a page here, 2 not yet.

- [Combining the Best of Two Worlds: A Hybrid Approach to Multilingual Coreference Resolution](https://md.research.elamur.ai/free/papers/chen-2012-combining-best-two-worlds-hybrid/)
- [Intra-Sentential Subject Zero Anaphora Resolution using Multi-Column Convolutional Neural Network](https://md.research.elamur.ai/free/papers/iida-2016-intra-sentential-subject-zero-anaphora/)
- [Coreference or Not: A Twin Model for Coreference Resolution](https://md.research.elamur.ai/free/papers/luo-2007-coreference-or-not-twin-model/)
- [Graph-Cut-Based Anaphoricity Determination for Coreference Resolution](https://md.research.elamur.ai/free/papers/ng-2009-graph-cut-based-anaphoricity-determination/)
- [Supervised Noun Phrase Coreference Research: The First Fifteen Years](https://md.research.elamur.ai/free/papers/ng-2010-supervised-noun-phrase-coreference-research/)
- [BESTCUT: A Graph Algorithm for Coreference Resolution](https://md.research.elamur.ai/free/papers/nicolae-2006-bestcut-graph-algorithm-coreference-resolution/)
- [Solving Hard Coreference Problems](https://md.research.elamur.ai/free/papers/peng-2015-solving-hard-coreference-problems/)
- [Global Learning of Noun Phrase Anaphoricity in Coreference Resolution via Label Propagation](https://md.research.elamur.ai/free/papers/zhou-2009-global-learning-noun-phrase-anaphoricity/)

## Cite

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

```bibtex
@inproceedings{ng2004learning,
  title = {{Learning Noun Phrase Anaphoricity to Improve Conference Resolution: Issues in Representation and Optimization}},
  author = {Ng, Vincent},
  booktitle = {Proceedings of the 42nd Annual Meeting of the Association for Computational Linguistics (ACL-04)},
  year = {2004},
  doi = {10.3115/1218955.1218975},
  url = {https://doi.org/10.3115/1218955.1218975}
}
```

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