Understanding Factuality in Abstractive Summarization with FRANK: A Benchmark for Factuality Metrics
Written for the Research library (claude-opus-5-5) from the paper text. Original — aclanthology.org/2021.naacl-main.383.pdf
Summary
Neural abstractive summarizers write fluent text that often misstates facts from the source. Existing factuality metrics could not be compared because there was no shared benchmark, and they all reduce factuality to a yes/no label for a whole summary.
The authors address both gaps. They design a typology of factual errors based on frame semantics and discourse analysis, with three levels:
- semantic frame errors (predicate, entity, circumstance),
- discourse errors (coreference, discourse links),
- content verifiability errors (information absent from the article, grammar broken enough to lose meaning).
Screened Amazon Mechanical Turk workers used this scheme to label every sentence of 2250 summaries. The summaries came from nine systems on CNN/DM and XSum, and the result is the FRANK dataset. Breaking factuality into categories made crowd judgements match expert ones closely.
FRANK is then used to profile system errors and to test how well automatic metrics agree with humans for each error type. Correlations are mostly modest, and each metric family has its own blind spots. The resource helps researchers see which kinds of errors a model or metric misses.
Key points
- Error categories: PredE, EntE, CircE, CorefE, LinkE, OutE and GramE, plus OthE (other) and NE (no error). Annotation is done per sentence.
- Data: 2250 summaries in total, from 5 models on CNN/DM (longer, multi-sentence summaries) and 4 models on XSum (single-sentence, more abstractive). Crowd–expert agreement reached κ = 0.86.
- Metrics evaluated with partial Pearson correlation:
- Rouge L, BERTScore and OpenIE (general summarization metrics),
- QAGS and FEQA (question generation/answering),
- DAE and FactCC (entailment).
- Main findings on metrics:
- FactCC has the best overall partial correlation.
- DAE correlates best with discourse errors.
- Both QGA metrics correlate negatively with discourse errors.
- Entailment metrics work best on pretrained models' CNN/DM outputs and degrade markedly on XSum.
- FRANK is larger than earlier factuality annotations, which covered 200 or 503 sentences or 470 summaries. Code, data and a leaderboard are announced at github.com/artidoro/frank.
Cited by
- The Internal State of an LLM Knows When It's Lying
- CLIFF: Contrastive Learning for Improving Faithfulness and Factuality in Abstractive Summarization
- QAFactEval: Improved QA-Based Factual Consistency Evaluation for Summarization
- Evaluating Large Language Models: A Comprehensive Survey
- TRUE: Re-evaluating Factual Consistency Evaluation
- A Survey on Hallucination in Large Language Models: Principles, Taxonomy, Challenges, and Open Questions
- Survey of Hallucination in Natural Language Generation
- LLMs-as-Judges: A Comprehensive Survey on LLM-based Evaluation Methods
- ChatGPT as a Factual Inconsistency Evaluator for Text Summarization
- Teaching Small Language Models to Reason
- Generating Training Data with Language Models: Towards Zero-Shot Language Understanding
- FActScore: Fine-grained Atomic Evaluation of Factual Precision in Long Form Text Generation
- Trusting Your Evidence: Hallucinate Less with Context-aware Decoding
- Beyond the Imitation Game: Quantifying and extrapolating the capabilities of language models
- MiniCheck: Efficient Fact-Checking of LLMs on Grounding Documents
- AlignScore: Evaluating Factual Consistency with A Unified Alignment Function
Cite
@inproceedings{pagnoni2021understanding,
title = {{Understanding Factuality in Abstractive Summarization with FRANK: A Benchmark for Factuality Metrics}},
author = {Pagnoni, Artidoro and Balachandran, Vidhisha and Tsvetkov, Yulia},
booktitle = {Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies},
year = {2021},
doi = {10.18653/v1/2021.naacl-main.383},
eprint = {2104.13346},
archivePrefix = {arXiv},
url = {https://doi.org/10.18653/v1/2021.naacl-main.383}
}References
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