Why some retrieval systems stumble on multi-step questions—and how to spot the trouble before it happens

Multi-hop retrieval is like following directions through a multi-floor building: you need the right clue on floor 1 to find the question for floor 2. When systems fail, they fail in clusters—certain *types* of queries trip them up predictably. New scoring methods can now identify which ones will struggle.

This means search and Q&A systems can now abstain gracefully instead of confidently giving you wrong answers—catching failure before your user sees it.