@inproceedings{wu-2026-relation,
title = "When Relation-Free Retrieval Is Not Relation-Aware: A Directionality Stress Test for Linear Graph {RAG}",
author = "Wu, Ding",
editor = "Sedoc, Jo{\~a}o and
Shu, Raphael and
Drozd, Aleksandr and
Akula, Arjun and
Rogers, Anna and
Giorgi, Salvatore and
Benton, Adrian",
booktitle = "Proceedings of the Seventh Workshop on Insights from Negative Results in {NLP}",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.insights-1.18/",
pages = "133--136",
ISBN = "979-8-89176-480-4",
abstract = "Relation-free graph retrieval avoids explicit relation extraction, but removing relation labels can weaken shallow ranking when argument order determines which evidence is correct. We test this boundary condition with the official LinearRAG retrieval-only pipeline. On a controlled set of 3,000 questions over nine asymmetric relation types, LinearRAG recovers the gold passage at rank 20 in 96.4{\%} of cases but ranks it first in only 18.2{\%}. Its top-1 output is a same-entity wrong-relation passage in 1,481 cases and a reversed-relation passage in 780 cases, for 2,261 direction errors (75.4{\%}); a further 108 cases are same-relation wrong-entity errors and are reported separately. A local Qwen2.5 reader shows that shallow retrieval errors mainly propagate as abstention or answer failure. The result is deliberately bounded: it diagnoses first-stage retrieval under asymmetric ambiguity, not the strongest possible reranked GraphRAG system. We recommend relation-sensitive shallow-ranking and reader-propagation checks in addition to aggregate recall."
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<abstract>Relation-free graph retrieval avoids explicit relation extraction, but removing relation labels can weaken shallow ranking when argument order determines which evidence is correct. We test this boundary condition with the official LinearRAG retrieval-only pipeline. On a controlled set of 3,000 questions over nine asymmetric relation types, LinearRAG recovers the gold passage at rank 20 in 96.4% of cases but ranks it first in only 18.2%. Its top-1 output is a same-entity wrong-relation passage in 1,481 cases and a reversed-relation passage in 780 cases, for 2,261 direction errors (75.4%); a further 108 cases are same-relation wrong-entity errors and are reported separately. A local Qwen2.5 reader shows that shallow retrieval errors mainly propagate as abstention or answer failure. The result is deliberately bounded: it diagnoses first-stage retrieval under asymmetric ambiguity, not the strongest possible reranked GraphRAG system. We recommend relation-sensitive shallow-ranking and reader-propagation checks in addition to aggregate recall.</abstract>
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%0 Conference Proceedings
%T When Relation-Free Retrieval Is Not Relation-Aware: A Directionality Stress Test for Linear Graph RAG
%A Wu, Ding
%Y Sedoc, João
%Y Shu, Raphael
%Y Drozd, Aleksandr
%Y Akula, Arjun
%Y Rogers, Anna
%Y Giorgi, Salvatore
%Y Benton, Adrian
%S Proceedings of the Seventh Workshop on Insights from Negative Results in NLP
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-480-4
%F wu-2026-relation
%X Relation-free graph retrieval avoids explicit relation extraction, but removing relation labels can weaken shallow ranking when argument order determines which evidence is correct. We test this boundary condition with the official LinearRAG retrieval-only pipeline. On a controlled set of 3,000 questions over nine asymmetric relation types, LinearRAG recovers the gold passage at rank 20 in 96.4% of cases but ranks it first in only 18.2%. Its top-1 output is a same-entity wrong-relation passage in 1,481 cases and a reversed-relation passage in 780 cases, for 2,261 direction errors (75.4%); a further 108 cases are same-relation wrong-entity errors and are reported separately. A local Qwen2.5 reader shows that shallow retrieval errors mainly propagate as abstention or answer failure. The result is deliberately bounded: it diagnoses first-stage retrieval under asymmetric ambiguity, not the strongest possible reranked GraphRAG system. We recommend relation-sensitive shallow-ranking and reader-propagation checks in addition to aggregate recall.
%U https://aclanthology.org/2026.insights-1.18/
%P 133-136
Markdown (Informal)
[When Relation-Free Retrieval Is Not Relation-Aware: A Directionality Stress Test for Linear Graph RAG](https://aclanthology.org/2026.insights-1.18/) (Wu, insights 2026)
ACL