Papers › Optimizing Bi-Encoder for Named Entity Recognition via Contrastive Learning
Optimizing Bi-Encoder for Named Entity Recognition via Contrastive Learning
Sheng Zhang, Hao Cheng, Jianfeng Gao, Hoifung Poon
We present a bi-encoder framework for named entity recognition (NER), which applies contrastive learning to map candidate text spans and entity types into the same vector representation space. Prior work predominantly approaches NER as sequence labeling or span classification. We instead frame NER as a representation learning problem that maximizes the similarity between the vector representations of an entity mention and its type. This makes it easy to handle nested and flat NER alike, and can better leverage noisy self-supervision signals. A major challenge to this bi-encoder formulation for NER lies in separating non-entity spans from entity mentions. Instead of explicitly labeling all non-entity spans as the same class Outside (O) as in most prior methods, we introduce a novel dynamic thresholding loss. Experiments show that our method performs well in both supervised and distantly supervised settings, for nested and flat NER alike, establishing new state of the art across standard datasets in the general domain (e.g., ACE2004, ACE2005) and high-value verticals such as biomedicine (e.g., GENIA, NCBI, BC5CDR, JNLPBA). We release the code at github.com/microsoft/binder.
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Code Syntology ran Syntology
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Tasks
Results from the paper archive 2025-07-28
| Task | Dataset | Model | Metric | Value | Rank at snapshot | Leaderboard | Report |
|---|---|---|---|---|---|---|---|
| Named Entity Recognition (NER) | BC5CDR | BINDER | F1 | 91.9 | #1 of 16 | Archive leaderboard | report |
| Named Entity Recognition (NER) | JNLPBA | BINDER | F1 | 80.3 | #4 of 17 | Archive leaderboard | report |
| Nested Named Entity Recognition | ACE 2004 | BINDER | F1 | 88.7 | #2 of 24 | Archive leaderboard | report |
| Nested Named Entity Recognition | ACE 2005 | BINDER | F1 | 89.5 | #1 of 25 | Archive leaderboard | report |
| Nested Named Entity Recognition | GENIA | BINDER | F1 | 80.5 | #8 of 26 | Archive leaderboard | report |
Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.
Methods
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