---
title: "Uncovering Discriminatory Behavior in LLM-Based CV Screening Systems with Composite Statistical Metamorphic Relations"
authors:
  - "Tetyana Turiy"
  - "Simon Speth"
  - "Alexander Pretschner"
doi: "10.24963/ijcai.2026/855"
url: "https://ijcai.org/proceedings/2026/855"
pdf: "https://ijcai.org/proceedings/2026/0855.pdf"
venue: "Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence"
year: 2026
pages: "7694-7702"
track: "Human-Centred AI"
keywords:
  - "Human-Centred AI: Humans and AI"
  - "Human-Centred AI: Machine Learning"
  - "Human-Centred AI: AI Ethics, Trust, Fairnes"
  - "Human-Centred AI: Multidisciplinary Topics and Applications"
---

# Uncovering Discriminatory Behavior in LLM-Based CV Screening Systems with Composite Statistical Metamorphic Relations

Tetyana Turiy, Simon Speth, Alexander Pretschner

*Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence*, pages 7694-7702. DOI: [10.24963/ijcai.2026/855](https://doi.org/10.24963/ijcai.2026/855)

## Abstract

Artificial intelligence (AI) applications are prone to reproducing existing patterns of marginalization, bias, and discrimination. The adoption of automated decision-making tools, particularly those based on large language models (LLMs), necessitates the detection and analysis of their discriminatory behavior to ensure compliance with anti-discrimination regulations. This work advances metamorphic testing for bias detection, aiming to (1) uncover discriminatory behavior in AI tools and (2) standardize the metamorphic test creation approach, rooting it in the legal and academic research on discrimination. To fill in these gaps, we introduce a metamorphic test creation workflow and evaluate it on the LLM-based CV screening use case. Our method yields a metamorphic relation (MR) catalogue of 8 atomic and 6 composite MRs, legally justified by Article 21 (1) of the Charter of Fundamental Rights of the European Union and sociologically motivated by the intersectionality theory. The resulting metamorphic test suite uncovers discriminatory failures for all 6 evaluated LLMs, totaling 1,272 defects across 7,800 test cases. Both the new atomic MRs and the composite MRs detect additional discriminatory defects for all LLMs. Composite MRs consistently uncovered more defects than their atomic counterparts, with failure rates increasing by on average 9% for Llama-3.1 8B and 25% for Llama-3.2 3B.