Symbol r
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averaged over a query set Q , where is the position of the first relevant result for query q . Mean reciprocal rank was formalised as the primary scoring metric for the TREC-8 Question Answering track, the first large-scale evaluation of domain-independent question answering systems, where it assigned a value of 1/r to a ranked list of candidate answers based on the rank r of the one judged correct [ 3 ] . It rewards getting the single most useful passage near the top and is blind to everything else in the list, which is exactly the property a downstream generator that reads only the first few passages needs measured.
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Equation 9 · AI Agents & Systems
Measuring What a RAG System Retrieves, Not Just What It Answers
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
averaged over a query set Q , where is the position of the first relevant result for query q . Mean reciprocal rank was formalised as the primary scoring metric for the TREC-8 Question Answering track, the first large-scale evaluation of domain-independent question answering systems, where it assigned a value of 1/r to a ranked list of candidate answers based on the rank r of the one judged correct [ 3 ] . It rewards getting the single most useful passage near the top and is blind to everything else in the list, which is exactly the property a downstream generator that reads only the first few passages needs measured.
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