Being well-calibrated means your confidence matches reality: the things you're 90% sure of happen about 90% of the time. Almost everyone is overconfident — our 90% ranges hold the truth far less than 90% of the time, because a narrow, precise-sounding range feels smarter than an honest one. The good news is that calibration is measurable, and it's trainable. This is a game to measure yours, then a dial to see why honest beats narrow.
Eight numbers nobody carries in their head. For each one, enter a low and a high bound so that you're 90% sure the true value sits between them — wide enough to be safe, tight enough to still mean something. Reveal each answer and watch how many of your 90% ranges actually hold.
Set a low and high bound you're 90% sure contains the answer. Aim to be wrong only about 1 time in 10.
Here's the same estimate made forty times over — each dot is one occasion you gave a 90% range. Drag the dial to change how wide you make that range, and watch two things pull against each other: how often you're right, and how much the range actually tells anyone. The goal isn't the narrowest range. It's the honest one.
Three things get muddled together whenever someone says "I'm sure." Pull them apart and the overconfidence bias — that steady pull toward narrow, precise-sounding ranges — stops fooling you.
| Lens | What it measures | The question it answers | Where it fails you |
|---|---|---|---|
| Accuracy | Whether a single answer turned out right. | "Was I correct this time?" | One hit or miss says almost nothing, and it ignores how sure you were when you said it. |
| Raw confidence | How sure you feel. | "How certain am I?" | Feelings aren't evidence. Confidence runs ahead of correctness — that's the overconfidence bias. |
| Calibration | Whether your confidence matches reality across many judgements. | "When I say 90%, is it true 90% of the time?" | You can't feel it from the inside. It has to be measured — and then it can be trained. |
The Forecast Cone is about uncertainty widening over time — a range that fans out the further ahead you project. The Calibration Game is about a different question: is the confidence you're stating right now honest at all? A cone can be beautifully drawn and still be dishonestly narrow at every point along it.
Reach for the cone when you're projecting forward and need to show uncertainty growing. Reach for calibration when you want to know whether any stated range — today's or next year's — can be trusted. Compare with the Forecast Cone →
Two percent either side of a number you can't actually pin down. It looks rigorous and sounds authoritative — and it's wrong far more than one time in ten.
Wider, and it admits what you don't know. Less impressive in the room — but right about nine times in ten, so people can actually plan on it.
A single confident number looks decisive and quietly buries everything you don't know. The same judgement, stated as a calibrated range, tells people the truth about how sure you really are. Four places it changes the decision.
The idea is simple; living it is the work — catching yourself mid-sentence about to give a number you can't defend, and widening it on purpose. Teams that estimate in honest ranges plan better, argue less about false precision, and get blindsided far less often. That's the work we do with the leaders and teams we coach: turning gut confidence into judgement you can actually bet on.
Talk to us about coachingThat's the whole test. If the things you're 90% sure of come true far less often, your confidence is inflated — and now you can see by how much.
Overconfidence is the default, so the fix has a direction: almost always, outward. Stretch your bounds until being wrong would genuinely surprise you.
How sure you feel and how often you're right are different numbers. Calibration is the discipline of closing the gap between them — and it improves with feedback.