RAG Interview Questions, issue 18, Jul 22, 2026
The Hop-Count Paradox
Senior ML Engineer interview at Google, and the interviewer asks:
“Adaptive RAG routes queries by predicted hop count, but nobody labels this question needs 2 hops. The paper bootstraps silver labels by brute-forcing every hop count and keeping whichever one got the right answer. What’s the ceiling that creates?”
Don’t say: “Silver labels are noisy, so you need more data cleaning.”
When predicting query complexity upfront silently memorizes your pipeline's weaknesses, and why treating retrieval as an evidence-gated policy prevents massive latency waste.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.