Reranking

Reranking seeks to improve search relevance by reordering the result set returned by a search with a different model.

Reranking computes a relevance score between the query and each data object, and returns the list of objects sorted from the most to the least relevant. Computing this score for all (query, data_object) pairs would typically be prohibitively slow, which is why reranking is used as a second stage after retrieving the relevant objects first.

As the reranker works on a smaller subset of data after retrieval, different, potentially more computationally expensive approaches can be used to improve search relevance.

With our reranker modules, you can conveniently perform multi-stage searches without leaving Weaviate.

In other words, you can perform a search - for example, a vector search - and then use a reranker to re-rank the results of that search. Our reranker modules are compatible with all of vector, bm25, and hybrid searches.

You can use reranking in a GraphQL query as follows:

{
  Get {
    JeopardyQuestion(
      nearText: {
        concepts: "flying"
      }
      limit: 10
    ) {
      answer
      question
      _additional {
        distance
        rerank(
          property: "answer"
          query: "floating"
        ) {
          score
        }
      }
    }
  }
}

This query retrieves 10 results from the JeopardyQuestion class, using a hybrid search with the query “flying”. It then re-ranks the results using the answer property, and the query “floating”.

You can specify which property of the JeopardyQuestion class you want to pass to the reranker. Note that here, the returned score will include the score from the reranker.

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