Reranking
Reranking
A technique for reordering candidates chosen by a search engine or AI into a more relevant sequence.
In Simple Terms
Reranking is a mechanism that takes the candidates an AI or search engine has already gathered and checks them again, more carefully, using a different method to reorder them. For example, it's used in systems that first sweep up around 100 documents that roughly match a keyword, then use a separate AI to rearrange them by how relevant they actually are. This makes it more likely that the information the user actually wants ends up near the top of the search results.
Behind the Name
The name is refreshingly literal: "reranking" means to rank again. It takes a set of results that already has an order and re-evaluates them to produce a new, more accurate order. Search engines and AI systems use it to push the piece of information a user is actually looking for closer to the top.
Take a Closer Look!
Reranking is a technique that takes information a search system or AI has already picked out and reorders it so the most relevant items rise to the top.
It's commonly used to efficiently find exactly what you're looking for within a huge pile of data.
In a typical search system, the flow is to first gather candidates quickly and roughly, then use reranking with a more advanced AI model to arrange them in a precise order.
Put simply, imagine quickly pulling around 100 books off a shelf that seem related to your keyword, then carefully reading through each one and putting the single best match back on top.
The first stage prioritizes speed, gathering candidates roughly, while the reranking stage that follows applies heavier computation to improve quality — together, the two stages deliver both speed and accuracy.
It's especially valuable in RAG systems, where an AI generates answers by referencing external documents, helping surface the most suitable reference material.
By feeding the AI information that's already been organized and refined through reranking, it reduces off-target answers and makes it easier to arrive at accurate ones.