Privacy-Preserving Heterogeneous Multi-LLM Federated Inference for Cognitive Diagnosis

Yagna Manasa Boyapati, Chong Yu, Tianyu Jiang, Justin Zhan


Abstract
Significant challenges remain in AI-driven educational systems in balancing privacy preservation with accurate cognitive diagnosis. In order to overcome this, we propose a federated inference framework in which several commercial LLM APIs collaborate without requiring access to raw student data or proprietary model internals. Using multiple federated entities, such as LLaMA-3.3-70B, GPT-4o-mini, and Claude-3-Haiku, our framework builds upon the heterogeneous multi-LLM architecture. The predictions generated by these entities are combined with ε-local differential privacy by adding Laplace noise locally to each entity’s prediction output before aggregation, while residual-based aggregation mitigates model heterogeneity. Our approach is predicated on an honest-but-curious trust paradigm in which API providers are presumed not to abuse submitted queries, and our differential privacy mechanism shields the published diagnostic results from external inference. We conduct rigorous privacy–utility analysis showing strong privacy guarantees with minimal accuracy loss, and extensive real-world evaluations across three educational benchmarks confirm the framework’s practical usability and cross-domain generalizability.
Anthology ID:
2026.findings-emnlp.1318
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
27913–27928
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1318/
DOI:
Bibkey:
Cite (ACL):
Yagna Manasa Boyapati, Chong Yu, Tianyu Jiang, and Justin Zhan. 2026. Privacy-Preserving Heterogeneous Multi-LLM Federated Inference for Cognitive Diagnosis. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 27913–27928, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Privacy-Preserving Heterogeneous Multi-LLM Federated Inference for Cognitive Diagnosis (Boyapati et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1318.pdf