Provenance-Grounded Gating and Adaptive Recovery in Synthetic Post-Training Data Curation

Soham Bhattacharjee, Karun Sharma, Vinay Kumar Sankarapu, Pratinav Seth


Abstract
Synthetic post-training pipelines commonly filter generated samples with reward models or holistic LLM judges, often relying on two assumptions: that a sample’s faithfulness can be judged without the exact source that produced it, and that rejected samples can be discarded rather than systematically recovered. We present a controlled study of both assumptions across gate configurations, recovery strategies, and generator scales, using adversarially injected corpora to provide ground-truth failure labels. We find that grounding faithfulness judgments in the exact source evidence improves over post-hoc retrieval for stronger judges and substantially outperforms reward-only filtering; hallucination and reward gates reject largely distinct sample populations supporting the need for both; and adaptive recovery, which diagnoses failures before repairing them, achieves higher yield and recovery rate than naive regeneration. Downstream fine-tuning quality is driven primarily by generator scale, with filtering and recovery providing their clearest gains when smaller generators are used. We release our evaluation corpus and experimental configurations to support reproducible pipeline design.
Anthology ID:
2026.findings-emnlp.2399
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
51556–51566
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2399/
DOI:
Bibkey:
Cite (ACL):
Soham Bhattacharjee, Karun Sharma, Vinay Kumar Sankarapu, and Pratinav Seth. 2026. Provenance-Grounded Gating and Adaptive Recovery in Synthetic Post-Training Data Curation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 51556–51566, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Provenance-Grounded Gating and Adaptive Recovery in Synthetic Post-Training Data Curation (Bhattacharjee et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2399.pdf