MEMERAG: A Multilingual End-to-End Meta-Evaluation Benchmark for Retrieval Augmented Generation

TL;DR

MEMERAG is a multilingual benchmark for evaluating retrieval augmented generation systems, using native-language data and expert annotations to better reflect cultural nuances and improve automatic evaluation methods.

Contribution

It introduces a multilingual, end-to-end meta-evaluation benchmark based on native-language data, enhancing the assessment of RAG systems across diverse languages.

Findings

High inter-annotator agreement in faithfulness and relevance assessments

Multilingual LLMs show varying performance across languages

Benchmark effectively identifies improvements from advanced prompting techniques

Abstract

Automatic evaluation of retrieval augmented generation (RAG) systems relies on fine-grained dimensions like faithfulness and relevance, as judged by expert human annotators. Meta-evaluation benchmarks support the development of automatic evaluators that correlate well with human judgement. However, existing benchmarks predominantly focus on English or use translated data, which fails to capture cultural nuances. A native approach provides a better representation of the end user experience. In this work, we develop a Multilingual End-to-end Meta-Evaluation RAG benchmark (MEMERAG). Our benchmark builds on the popular MIRACL dataset, using native-language questions and generating responses with diverse large language models (LLMs), which are then assessed by expert annotators for faithfulness and relevance. We describe our annotation process and show that it achieves high inter-annotator agreement. We then analyse the performance of the answer-generating LLMs across languages as per the human evaluators. Finally we apply the dataset to our main use-case which is to benchmark multilingual automatic evaluators (LLM-as-a-judge). We show that our benchmark can reliably identify improvements offered by advanced prompting techniques and LLMs. Our dataset is available at https://github.com/amazon-science/MEMERAG