AI-ENGINEERING
    intermediate

    LLM-as-a-Judge

    AI Engineer path · lesson 88 of 124
    The idea
    An LLM judge is a quick but impressionable contest referee: it tends to favor whoever went first and whoever talked longest. Swap the order or trim the waffle and the verdict can change — so you control for those before trusting the score.
    How to use
    Swap the answer order and toggle length-normalize to watch the judge flip its verdict — see position bias and verbosity bias in action.
    PromptWhat is our refund window? (A is concise & precise; B is correct but padded.)
    Judge LLM scores each on the rubric…
    Answer A9.2

    Refunds: within 30 days.

    true 8.2 +1 position
    Answer B8.6

    Regarding refunds, customers are generally able to request one within a window of approximately thirty days from purchase, subject to standard terms.

    true 8.0 +0.6 verbosity
    Judge picks Answer A. ✓ Correct here — but flip the order and watch the winner change.

    Key insight

    An LLM judge scales evaluation but isn’t neutral: just swapping the order can flip the winner (position bias), and length alone inflates scores (verbosity bias). Average over both orders, normalize length, anchor the rubric, and validate against humans before trusting it.

    Build a judge you can trust

    Sequence

    Order the steps that make LLM-as-a-judge defensible.

    Tap a piece, then tap where it goes — or drag it. Tap the tray to take one back.

    1. 1Drop a step here
    2. 2Drop a step here
    3. 3Drop a step here
    4. 4Drop a step here
    5. 5Drop a step here
    6. 6Drop a step here
    6 pieces left to place

    Test your knowledge

    20 questions
    Question 1 of 20
    Score: 0

    Which is a well-known bias of LLM judges?

    The short version

    An LLM judge is a quick but impressionable contest referee: it tends to favor whoever went first and whoever talked longest. Swap the order or trim the waffle and the verdict can change — so you control for those before trusting the score.

    Interview Questions

    OpenAI
    Anthropic
    Scale AI
    OpenAI
    Anthropic
    Anthropic
    Scale AI
    OpenAI
    Scale AI
    GitHub
    Google
    Anthropic

    Love this visualization?

    Sign up to track your progress, earn achievements, use the AI assistant, and access your personal learning dashboard.

    100% free • No credit card required