Summary
In this chapter, we discussed a wide range of metrics for evaluating both retrieval quality and generation performance, including traditional information retrieval metrics such as Recall@k, Precision@k, MRR, and NDCG, as well as more RAG-specific metrics such as groundedness, faithfulness, and answer relevance. We explored various techniques for measuring these metrics, including automated methods based on NLI and QA models, and human evaluation approaches using rating scales, comparative judgments, and task-based assessments.
We emphasized the crucial role of human evaluation in capturing the nuanced aspects of RAG performance that are difficult to assess with automated metrics alone. We also discussed best practices for designing and conducting human evaluations, such as providing clear guidelines, training annotators, measuring inter-annotator agreement, and conducting pilot studies. We need to keep in mind that tradeoffs between automated and human evaluation will be...