Equation 4 · Part 1 · Measuring What a RAG System Retrieves, Not Just What It Answers
Symbol k
What this part means
k is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Its job in the formula
k 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 k→Article meaning
The passage around this formula
Recall at k is the simplest of the four: the fraction of relevant documents that appear anywhere in the top k results. It answers one question only — did the evidence make it into the candidate set at all — and says nothing about where within that set it landed. Mean reciprocal rank answers the positional question for the single best hit:
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.
Open the illustrated variables: a letter stands for a value guide →
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Sources cited in the article section
- [3] The TREC-8 Question Answering Track Report ↗
- [2] BEIR: A Heterogeneous Benchmark for Zero-shot Evaluation of Information Retrieval Models ↗
These citations provide research context; check each source for the exact claim it supports.