"I Don't Know" -- Towards Appropriate Trust with Certainty-Aware Retrieval Augmented Generation

TL;DR

This paper introduces CERTA, a retrieval-augmented system that conveys uncertainty in LLM answers to foster appropriate trust, supported by a new benchmark with diverse question-context pairs.

Contribution

The paper presents a novel CERTA system that integrates relevance-based uncertainty reflection and a comprehensive benchmark for non-objective questions.

Findings

CERTA improves identification of uncertain answers

It reduces over-agreement in responses

CERTA promotes cautiousness in moral judgments

Abstract

Achieving the right amount of trust in AI systems is important, but challenging. The problem is exacerbated with the rise of Large Language Models (LLMs) as they provide human-level communication capabilities, but potentially hallucinate in the content that they generate. Moreover, they express over-confidence in their answers, making it difficult for users to judge their truthfulness. An important human value that users seek is benevolence, which can be met by LLM's self-reflection leading to reliable and honest answers. Accordingly, this paper proposes conveying appropriate levels of self-reflected certainty to build appropriate trust. Our contributions are twofold: 1) We develop CERTA (Certainty Enhanced RAG for Trustworthy Answers), a specialized Retrieval Augmented Generation (RAG) system that incorporates the relevance between question, context, and answer to reflect its uncertainty in answering questions; 2) We create the Certainty Benchmark with 90 question-context pairs of non-objective questions, divided over four categories (factuality, preference, sycophancy, morality) and three types of contexts (relevant, incomplete, irrelevant). We run experiments with a baseline RAG system and three CERTA settings using two LLMs. Our evaluations indicate that CERTA helps identify answers that are uncertain, decreases the cases of over-agreeing, and provides cautious behavior when prompted for moral judgments.