Enhancing Trustworthiness with Mixed Precision: Benchmarks, Opportunities, and Challenges
Guanxi Lu, Hao Mark Chen, Zhiqiang Que, Wayne Luk, Hongxiang Fan
TL;DR
This paper explores how quantization affects the trustworthiness of large language models, revealing instability at low bit-widths across quantization methods. It introduces a precision-ensemble voting approach that combines multiple mixed-precision variants to stabilize predictions and improve trustworthiness metrics by up to $5.8\%$, while preserving multi-domain task performance. The work provides a framework for evaluating trustworthiness under compression, demonstrates method- and metric-dependent effects, and outlines opportunities for joint compression, multi-modal extensions, and algorithm-system-hardware co-design to enable safe, efficient deployment of quantized LLMs.
Abstract
Large language models (LLMs) have shown promising performance across various tasks. However, their autoregressive decoding process poses significant challenges for efficient deployment on existing AI hardware. Quantization alleviates memory and compute pressure by compressing weights, activations, and KV caches to low precisions while preserving generation quality. However, existing quantization frameworks typically focus on perplexity or classification accuracy, often omitting critical trustworthiness metrics. This gap introduces risks when applying quantized LLMs to downstream high-stakes domains such as finance and healthcare. In this work, we systematically investigate the impact of quantization on four trustworthiness metrics (adversarial robustness, fairness, machine ethics, and out-of-distribution robustness) and identify the instability across compression ratios and quantization methods. Building on these observations, we develop a novel precision-ensemble voting approach that leverages predictions from mixed-precision variants of the same model and consistently improves performance by up to $5.8\%$ on trustworthiness metrics. Our results highlight the importance of considering trustworthiness when developing model compression techniques and point to research opportunities at the intersection of compression and trustworthiness for safety-critical applications.
