Quantifying Retrieval Quality in GraphRAG: A Schema-Agnostic Approach

Thibaud Vanmechelen, Alexandre Achten, Zaineb Gabsi, Sabri Skhiri


Abstract
While LLMs have achieved significant success in natural language tasks, their tendency to hallucinate remains a critical challenge. RAG tries to address this issue by grounding models in external data; however, standard vector-based RAGs often fail when working with highly interconnected datasets. GraphRAG has emerged as a superior alternative in this setting by modelling the relational topology, yet evaluating GraphRAGs remains challenging. Current benchmarks predominantly focus on the final LLM-generated output frequently overlooking the structural accuracy of the underlying retrieval process. In this paper, we propose a novel schema-agnostic framework for the automated generation of synthetic evaluation datasets from KGs. Unlike previous approaches, our framework establishes a rigorous, deterministic ground truth to specifically quantify the retriever performance across nine distinct query categories, including multi-hop and aggregation tasks. We demonstrate the utility of this benchmark by applying it to a biochemical KG and evaluating four diverse retrieval architectures. Our results indicate that agentic, LLM-driven retrievers provide the highest recall and reasoning capacity, effectively navigating complex topologies where other methods struggle. This work provides a robust, scalable methodology for performance tracking, shifting the evaluation of GraphRAG toward a more topologically precise standard.
Anthology ID:
2026.kallm-1.18
Volume:
Proceedings of the Knowledge Graphs and Large Language Models Workshop (KG-LLM) @ LREC26
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Gilles Sérasset, Katerina Gkirtzou, Michael Cochez, Jan-Christoph Kalo
Venues:
KaLLM | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
176–189
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-kgllm-18
DOI:
10.63317/5h4oct2t73a2
Bibkey:
Cite (ACL):
Thibaud Vanmechelen, Alexandre Achten, Zaineb Gabsi, and Sabri Skhiri. 2026. Quantifying Retrieval Quality in GraphRAG: A Schema-Agnostic Approach. In Proceedings of the Knowledge Graphs and Large Language Models Workshop (KG-LLM) @ LREC26, pages 176–189, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
Quantifying Retrieval Quality in GraphRAG: A Schema-Agnostic Approach (Vanmechelen et al., KaLLM 2026)
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