Exploring Safety-Utility Trade-Offs in Personalized Language Models
This addresses fairness issues for diverse users in daily LLM applications, but it is incremental as it quantifies an existing concern without proposing a fundamentally new solution.
The paper tackles the problem of personalization bias in large language models (LLMs), where performance varies based on user identity, and finds significant variance in safety-utility trade-offs across models like Llama, Mistral, GPT-3.5, and GPT-4o.
As large language models (LLMs) become increasingly integrated into daily applications, it is essential to ensure they operate fairly across diverse user demographics. In this work, we show that LLMs suffer from personalization bias, where their performance is impacted when they are personalized to a user's identity. We quantify personalization bias by evaluating the performance of LLMs along two axes - safety and utility. We measure safety by examining how benign LLM responses are to unsafe prompts with and without personalization. We measure utility by evaluating the LLM's performance on various tasks, including general knowledge, mathematical abilities, programming, and reasoning skills. We find that various LLMs, ranging from open-source models like Llama (Touvron et al., 2023) and Mistral (Jiang et al., 2023) to API-based ones like GPT-3.5 and GPT-4o (Ouyang et al., 2022), exhibit significant variance in performance in terms of safety-utility trade-offs depending on the user's identity. Finally, we discuss several strategies to mitigate personalization bias using preference tuning and prompt-based defenses.