Step-by-Step: Separating Planning from Realization in Neural Data-to-Text Generation
Written for the Research library (claude-opus-5-5) from the paper text. Original — aclanthology.org/N19-1236.pdf
Summary
End-to-end neural data-to-text systems produce fluent text, but they often drop, repeat or invent facts, and they offer no way to steer the structure of the output. The authors split generation into two stages and test the idea on the WebNLG benchmark, where inputs are sets of DBPedia RDF triplets. First, a symbolic planner builds a text plan: a sequence of ordered trees. The plan fixes how facts are grouped into sentences, the order of sentences and facts, and the direction in which each relation is verbalized. By construction, every input triplet appears in the plan exactly once. The plan is then linearized and given to an NMT-based realizer that only has to choose the wording. To train the realizer, the authors automatically pair reference texts with plans that match them. The same annotated data drives a scoring method that selects good plans for new inputs. The resulting system matches or exceeds a strong neural baseline on BLEU and human fluency ratings, and it is clearly more faithful to the input. It can also produce diverse, controllable outputs. This shows that the classic split between planning and realization still pays off in neural NLG.
Key points
- Plan representation: each sentence plan is a labeled ordered tree whose edges carry an RDF relation and a direction (→/←). Facts sharing an entity are linked as chains or siblings. For small WebNLG inputs, all candidate plans can be enumerated exhaustively by grouping the facts and running DFS traversals.
- Human fluency evaluation:
- The plan-based system (BestPlan) performed on par with the end-to-end StrongNeural baseline.
- It beat the earlier human-evaluation leader, UPF-FORGe.
- It was rated below the human References, partly because it does no referring expression generation.
- Realizer consistency with plans (Table 4):
- For the best plan, all requested entities were realized in 98.9% of sentence plans on the seen test set and 66.7% on the unseen set (93.6% / 41.3% for the top 10% of plans).
- Whenever all entities were realized, their order followed the plan in essentially 100% of cases.
- Diversity: realizing random plans from the top 10% (RandomPlan-1/2/3) produced quite different texts. Automatic scores dropped only modestly and stayed stable across random seeds.
- Released resources: the code and the WebNLG corpus extended with matching plans are available at github.com/AmitMY/chimera.
Cited by
- Encode, Tag, Realize: High-Precision Text Editing
- DART: Open-Domain Structured Data Record to Text Generation
- An Error Analysis Framework for Shallow Surface Realization
Cite
@inproceedings{moryossef2019step,
title = {{Step-by-Step: Separating Planning from Realization in Neural Data-to-Text Generation}},
author = {Moryossef, Amit and Goldberg, Yoav and Dagan, Ido},
booktitle = {Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers)},
year = {2019},
doi = {10.18653/v1/n19-1236},
url = {https://doi.org/10.18653/v1/n19-1236}
}References
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