MetaSyn shows agents recover under 53% of relevant literature despite 91% retrieval recall.

A June 15 paper introduces 442 expert-curated Nature Portfolio meta-analyses against a 140,000-article PubMed corpus, benchmarking twelve pipeline configs. No system recovered more than 52.7% of ground-truth included literature, even at 90.9% retrieval recall at K=200. The bottleneck isn't finding documents, it's deciding which ones actually qualify. This is hard evidence that RAG recall metrics overstate real research competence. If you ship anything that screens or filters retrieved content, your recall number is lying to you about end-to-end quality.