Senior interview question
How do you size the candidate pool for a reranker?
Model answer
From where the right chunk usually lands. A reranker can only reorder what it's given: if relevant chunks typically sit at rank 8, a pool of 3 can't help.
Each extra candidate is another model run, so the pool trades quality against latency, as Nogueira et al. note for multi-stage ranking. Measure recall at the pool size, then precision at the top after reranking.
Practise the rest
6 Hybrid & reranking questions, 492 in all, each with a model answer. Free.
More Hybrid & reranking interview questions
- What is hybrid search?
- How does reciprocal rank fusion work, and why use ranks rather than scores?
- When can fusion make retrieval worse?
- What's the difference between an embedding model and a reranker?
- A reranker fixes most of your misses but still prefers “safe for children over three” to “not safe for children under three”. What do you conclude?