BENCHMARKS AND LEADERBOARDS

THE LANGUAGE MODEL EVALUATION HARNESS Chapter 31 explained what an evaluation harness is. There is a famous open-source example for language models, called the Language Model Evaluation Harness. Open-source means that the code is public and anyone may use and inspect it. This framework, created and maintained by the research community known as EleutherAI, lets you run many different benchmark test suites against a model in a standardized, repeatable way. You choose a model and a list of benchmark tasks, the framework feeds each task to the model in a consistent format, applies the standard scoring method, and reports the results. Because everyone using the framework follows the same procedure, results from different research groups become more comparable. A subtle point deserves emphasis. Even tiny differences in how a question is formatted, such as the exact wording of the prompt or the order of multiple-choice options, can shift scores. A shared harness reduces these hidden differences, which is much of its value. Note that this tool is mainly designed to test models rather than whole agents with tools, which leads to the next section.