Equation 20 · Part 2 · Measuring What a RAG System Retrieves, Not Just What It Answers
Symbol R
What this part means
the event that the retriever’s top- k results contain sufficient evidence to answer the query, and let “correct” mean the generated answer is judged faithful and relevant.
Its job in the formula
R is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol R→Article meaning
Where the article explains it
Let R be the event that the retriever’s top- k results contain sufficient evidence to answer the query, and let “correct” mean the generated answer is judged faithful and relevant.
The passage around this formula
…side only. The two terms on the right are exactly what generation metrics and retrieval metrics separately illuminate, and the second term is the one an aggregate score cannot see at all. P( R) is the probability the model answers correctly despite the retriever having failed — because the underlying language model already carried the answer parametrically, because the question was easy enough to guess, or, in the worst case, because the benchmark’s own answer had leaked into the…
Learn the underlying idea
A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.
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Sources cited in the article section
- [8] Benchmarking Large Language Models in Retrieval-Augmented Generation ↗
- [9] CRAG: Comprehensive RAG Benchmark ↗
These citations provide research context; check each source for the exact claim it supports.