Experimentation and validation of LLM performance is critical when building LLM-driven systems that must reliably deliver a service, from customer service chat bots to intelligence analysis tools. To help teams meet the need for rigorous evaluation methods, a research team in the SEI's AI Division led by Violet Turri has developed the Evaluating Large Language Models [(ELM)]() library, which is built on best practices for LLM evaluation and benchmarking. In the latest episode from the Carnegie Mellon University Software Engineering Institute, Turri sits down with Katie Robinson, a design researcher also in the SEI's AI division, to discuss the ELM library, which turns evaluation from an ad-hoc process into a repeatable, extensible framework.