ResearchResearch paperRetrieval, RAG & Search1 source · Oct 20, 2026

DeclineCraft: A RAG Abstention Benchmark for Jointly Measuring Combined Retrieval and Parametric Knowledge

We introduce DeclineCraft, a dynamic abstention benchmark whose unanswerable questions target Minecraft feature additions after a corpus cut-off, with audits of possible parametric exposure.

Key points

  • Reliable retrieval-augmented generation (RAG) requires recognizing when neither retrieved documents nor parametric knowledge supports an answer.
  • Later cut-offs support evaluation of future models.
  • We find that (1) single-shot retrieval significantly raises CAR in 38 of 40 configurations (model and thinking setting) versus no retrieval.
  • Adding query rewriting and reranking to hybrid (dense & sparse) retrieval lowers CAR for all 12 models tested.

Sources (1)

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