Interview Question
A RAG application has good latency but poor answer quality. How do you isolate the problem?
What the interviewer is testing
- Evaluation design
- Retrieval isolation
- Grounding reasoning
Real-World Sample Answer
I would approach “A RAG application has good latency but poor answer quality. How do you isolate the problem?” by clarifying the requirements first, then using these considerations: in a real interview, i would not jump straight to a technology choice. for “a rag application has good latency but poor answer quality. how do you isolate the problem?”, i would first measure retrieval separately from generation. then i would inspect chunking, metadata, ranking, and context construction and test model behavior independently. i would also use a representative evaluation set. finally, i would add grounding and fallback checks. i would make the assumptions explicit and explain what evidence or production signals would make me revisit the decision.. I would state my assumptions and defend the trade-offs rather than presenting the choice as universally correct.
What a Strong Answer Should Cover
In a real interview, I would not jump straight to a technology choice. For “A RAG application has good latency but poor answer quality. How do you isolate the problem?”, I would first measure retrieval separately from generation. Then I would inspect chunking, metadata, ranking, and context construction and test model behavior independently. I would also use a representative evaluation set. Finally, I would add grounding and fallback checks. I would make the assumptions explicit and explain what evidence or production signals would make me revisit the decision.
Common Mistakes
- Changing models before proving the retrieval problem
- Evaluating only final answers
- Ignoring evaluation-set quality
Interviewer Follow-ups
- What assumptions would you clarify before committing to the design?
- What changes if the scale, reliability target, security requirement, or budget changes?
- What is the biggest failure mode in your proposed approach?