Navigating the Unknown: Intent Classification and Out-of-Distribution Detection Using Large Language Models

AbstractOut-of-Distribution (OOD) detection is a challenging task that requires great generalization capability for the practicality and safety of task-oriented dialogue systems (TODS). With the dawn of large language models (LLMs), their enhanced ability to handle diverse patterns and contexts may aid in addressing this challenging task. In this paper, we investigate the current performance of LLMs in the near-OOD setting, where OOD queries belong to the same domain but different intents. To take advantage of out-of-the-shelf capabilities of LLMs, we do not use fine-tuning. We study the performance of one of the leading frontier models, GPT-4o, in 3 well-known public datasets and 3 in-house datasets, using 10 different methods and prompt variations. We study the performance of different prompts and techniques in Gemini 1.5 Flash and Llama 3.1-70b. We investigate the effect of increasing the number of In-Distribution (ID) intents. We propose a novel hybrid method that is cost-efficient, high-performing, highly robust, and versatile enough to be used with smaller LLMs without sacrificing performance. This is achieved by combining ID success of smaller text classification models and high generalization capabilities of LLMs in OOD detection.