Measuring and Reducing LLM Hallucination without Gold-Standard Answers via Expertise-Weighting

LLM is known to provide factually inaccurate information that appears to be confident, i.e. hallucination. It is currently a major obstacle to the reliability and trustworthiness of LLM [13, 34, 21]. An essential step towards solving this problem is measuring hallucinations. However, this is challenging from a data perspective as existing metrics presume that benchmark datasets posses gold-standard answers, i.e. "best" or "correct" answers written by humans [16]. The requirement of such answers imposes two fundamental limitations on hallucination measurement: 1) hiring human annotators to produce gold-standard answers is costly in both time and money [4, 43, 38]; 2) gold-standard answers are prone to natural human errors [7, 6, 49]. To this end, we take a step forward and propose a framework which measures the LLM hallucinations without the requirement of gold-standard answers. Our framework is partially inspired by the literature on learning with noisy labels [23, 18, 19], where there are no ground-truth labels for verifying the quality of imperfect human annotations [43, 38, 20], detecting annotation errors [48, 26, 47], or training models robustly [42, 3, 17, 36, 39]. Our basic idea is simple: leveraging off-the-shelf and high-quality LLMs to generate answers that serve as a proxy for gold-standard answers. The primary challenge in such an approach is how to properly weigh the expertise of each LLM for a given question x, without a priori knowledge of the true (i.e.