• LLM-as-a-judge = using an LLM to evaluate LLM outputs, e.g. asking "Is this text polite?" or "Is this text concise?" and getting a response 0:18
  • It works both for experimentation (offline testing) and for live monitoring in production 0:18

Why it isn't "cheating"

The common objection — "how can an LLM be trusted to evaluate its own outputs?" — misses what the judge is actually asked to do:

  • The evaluator is not redoing the work; it does something narrower: classify or evaluate text against specific criteria 0:35
  • It's much easier to critique than to create — spotting errors is easier than avoiding them, even for LLMs 0:35
  • Asymmetry of jobs: the main product (e.g. a chatbot) handles user inputs, memory, tools, and complex instructions; the evaluator has one simpler job, e.g. "Is this response respectful?" 1:00
  • The chatbot might get tricked by a malicious user mid-conversation, but the evaluator only looks at the final text and judges it on its merits 1:00