MagicBeanStalk: 88% of RLVR data trapped in zero advantage, recursive synthesis adds 8.6 points

Lianhuiq · x · 2026-10-15

An arXiv paper by Ximing Lu, Aviral Kumar, Jan Kautz, Yejin Choi, and David Acuna shows 88% of pooled open-source RLVR math problems fall into a "zero-advantage trap": for a fixed policy and rollout budget they pass or fail every rollout, yielding no learning signal, and filtering merely discards hard problems. MagicBeanStalk synthesizes policy- and budget-calibrated problems via top-down decomposition plus bottom-up recursive synthesis, guided by three empirical principles (hard seeds specify what to synthesize; preserve reasoning operations; calibrate difficulty to policy and budget). Results: +8.6 points across 8 math benchmarks for gpt-oss-120b and +5.4 for DeepSeek v4 Flash.

Related event: Study Finds 88% of RLVR Data Trapped in Zero-Advantage Pit, Recursive Synthesis Offers Fix(2 posts)→

Original post →

More from Research

Research channel →