counterfactual-trajectory-utility-2a086719·1 events·first seen Aliases: Counterfactual Trajectory Utility
A new arXiv paper demonstrates empirically that static retrieval relevance scores are nearly statistically independent from causal utility in multi-step agentic search (Spearman rho = -0.026 across 23,322 document observations). Using a ReAct-style agent over HotpotQA with counterfactual trajectory replays, the authors show that roughly a third of documents are causally load-bearing ('bridge documents') while appearing useless to a static reader. The mechanism is identified: bridge documents supply discriminative entities that redirect subsequent queries, meaning optimizing static RAG utility does not deliver agentic utility.