Equation 21 · 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
The reverse failure sits inside the first term. P( R) can be low even when R holds — the right evidence was retrieved and still the generator wrote an unfaithful, evasive, or contradicted answer — and a retrieval-only evaluation, which never inspects generation at all, cannot detect this. Chen and colleagues benchmarked RAG systems along four…
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.