RAG corpus expansion causes answer churn even when accuracy barely changes, audit method proposed

_reachsumit · x · 2026-08-25

The paper shows that expanding a RAG system's corpus can change many answers even when accuracy barely moves. They propose a Snapshot Compatibility Audit to estimate excess answer churn. In a 400-question Natural Questions study, normalized-exact and blinded-semantic excess churn are 6.44 and 10.25 percentage points, while exact-match accuracy changes by only -1.50 points.

Related event: CMU study reveals hidden answer drift in RAG systems during index updates(2 posts)→

Original post →

More from Research

Research channel →