Interactive lab / LLM Core

Calibration lab: make 90% confident mean 90% right

Score 2,000 synthetic answers, read the reliability diagram, fit temperature and bias, set an abstention threshold and survive a domain shift.

By Sandeep Belgavi · Published 2026-10-30

Evidence label: deterministic synthetic model. The lab simulates a question-answering model rather than calling one. Each synthetic question has a difficulty that sets the true chance the model is right; the model sees a noisy version of that chance and reports a confidence that is sharpened (overconfident) to a degree you can change with the chat-tuned event. Multi-token answers add phrasing tokens whose probabilities have nothing to do with correctness, and the agreement signal samples k extra answers. The lab then computes ECE, AUROC, coverage and answered accuracy exactly as described in the article. All numbers are calculated from this synthetic model.

Play the lab

How to play

Choose a confidence signal, then adjust the calibration temperature T and bias b, which transform the log-odds as z / T + b. Set an answer threshold to abstain on low-confidence questions, and change the number of bins to see how the ECE estimate moves. The insight panel reports the temperature and bias that fit the current data best, which is what fitting on a labelled calibration set would give you. Inject a chat-tuned model, a new question domain or multi-token answers, and use the presets as reference points. Missions unlock in order; stars reward lower calibration error, higher coverage or a cheaper signal.

What the model assumes

Difficulty is normally distributed and maps to a probability of being right through a logistic curve, giving about 76% accuracy by default. The model's internal estimate is that probability's log-odds plus Gaussian noise, scaled by 1.35 (1.9 when chat-tuned) and shifted upward. In the new domain, the true probability falls by 1.6 log-odds units on half the questions, but the model's estimate does not. Multi-token answers have 1 to 12 tokens; extra tokens have probabilities between 0.55 and 0.99 unrelated to correctness. Agreement samples match the main answer with a probability driven by the model's internal estimate. Each model call costs an illustrative $0.002.

What it cannot tell you

Real miscalibration is not a single logistic distortion; it varies across topics, prompt formats and answer types, and semantic equivalence between differently worded answers matters for agreement signals. The lab ignores label noise, the cost of labelling, isotonic regression and conformal methods. Use it to understand what each metric and fix does, then measure calibration on your own labelled traffic.

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