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
- 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)