Evidence Hub

Label-Free Evaluation of Retrieval-Augmented Generation in a University Policy Chatbot

Lusine Hayrapetyan

ACM Technical Symposium on Computer Science Education (SIGCSE), 2026

1 citation

Abstract

Retrieval-augmented generation (RAG) is a common approach for building chatbots that combine fluent language generation with access to domain-specific knowledge. However, these systems often produce answers that are plausible but weakly supported by retrieved documents or that cite irrelevant sources. Evaluating RAG chatbots is difficult because it requires measuring both how well answers address user queries and how well they are grounded in retrieved content. University policy documents provide a useful test case. They are lengthy, formal, and regularly updated, yet they guide routine decisions for students and faculty. The combination of structured policies and varied user questions makes this domain well suited for systematic label-free evaluation. This study evaluates a RAG chatbot deployed at a large public university with over 700 pages of institutional policies. A dataset of 140 interaction logs was collected, and a refined subset was analyzed. Automated methods measured relevance (alignment of answers with questions), groundedness (alignment with retrieved text), and retrieval effectiveness (Recall@k and Mean Reciprocal Rank). Results show moderate performance on both relevance (0.64) and groundedness (0.66), with strong retrieval coverage but weaker ranking. Additional analyses examined how input clarity, phrasing style, and conversation behavior influenced chatbot performance.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free