Glossary · Retrieval & generation
Reranker
A second-stage model or scoring function that reorders a small candidate set using a richer comparison between the query and each candidate.
Why it matters
Fast first-stage retrieval maximizes candidate coverage, while reranking can improve which evidence reaches the limited context window.
In practice
Retrieve 50 candidates with hybrid search, score each query-document pair with a cross-encoder, and pass the top 5 supported chunks to generation.
Common confusion
A reranker does not search the entire corpus. It only reorders candidates that retrieval already found.
Related terms
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