arXiv Computation and Language By Miguel Mochizuki Silva, Samuel Ismael, Mateus C. Dias, Tha\'is Gaud\^encio, Yuri Malheiros, Barufaldi

How Ground Truth Shapes Retrieval Scores: Evidence-Aware Evaluation of a Retrieval-Augmented Generation System for Breast Lesions

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The study introduces an evidence-aware evaluation protocol for a retrieval‑augmented generation system focused on breast lesion management literature. Using an 18‑document corpus and 18 queries, the authors compared dense embeddings, BM25, and cross‑encoder reranking across various chunk sizes and overlaps, finding that a hybrid retriever with 384‑token chunks and 20% overlap achieved top‑three retrieval success for 17 of 18 queries and high recall and precision metrics. Expanding ground‑truth relevance annotations increased recognized evidence spans and accepted chunk targets, though retrieval rankings remained unchanged, underscoring the sensitivity of evaluation to annotation coverage.

Machine-generated by The Flow from the publisher's headline and feed description — not written or checked by a human. The full article lives at arXiv Computation and Language.

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