Causal Evidence Extraction and Triangulation in Crisis Reports using Large Language Models: A ReliefWeb-based Study

arXiv:2608.04576 · cs.CL · Submitted 2026-08-05 · Read on arXiv

Yuanjun Zhang, Mourad Oussalah

cs.CL

Submitted: 2026-08-05

Journal ref: Findings of the Association for Computational Linguistics: ACL 2026, pages 32478-32491, 2026

DOI: 10.18653/v1/2026.findings-acl.1626

License: http://creativecommons.org/licenses/by/4.0/

The gist: Humanitarian reports are long, noisy, and multi-topic, making it difficult to consolidate decision-relevant causal evidence.

Terminology

Abstract

Humanitarian reports are long, noisy, and multi-topic, making it difficult to consolidate decision-relevant causal evidence. We present a ReliefWeb study (2000-2024) and a two-stage Large Language Model (LLM) pipeline that extracts structured intervention-outcome records with direction and strength attributes. Query-conditioned extraction restricts output to a specified intervention class, reducing retrieval-induced over-extraction, while snippet grounding links each relation to supporting text for auditability and classification. In an expert-annotated dataset of 100 reports, the best closed-source LLM achieved a weighted F1 score of 90.73% with strong cost-efficiency, while Llama-3.1-8B with supervised fine-tuning reached 94.15% weighted F1 score. We further propose context-preserving triangulation that aggregates strength-weighted evidence within disaster times source cells, applies Laplace smoothing and equally weights cells to quantify cross-context convergence via a Level-of-Evidence score. Applied to cash assistance, food-related outcomes show strong positive convergence (LoE=0.865) and stable long-horizon trajectories.

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