Equation 21 · Retrieval Is an Evidence System, Not a Memory
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The first factor is a pure retrieval quantity: recall at k , measurable against relevance judgements with no generator involved, using the established information-retrieval apparatus that BEIR standardised [ 6 ] . The second is a pure generation quantity: given that sufficient evidence was present, did the model use it faithfully? Es and colleagues built RAGAS to score exactly this separation — retrieval effectiveness, the faithfulness with which the model uses retrieved passages, and generation quality — as a reference-free evaluation that does not require ground-truth answers, enabling faster iteration [ 17 ] .
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- [6] BEIR: A Heterogenous Benchmark for Zero-shot Evaluation of Information Retrieval Models ↗
- [17] Ragas: Automated Evaluation of Retrieval Augmented Generation ↗
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