Decision Mastery Check the Evidence

Base-Rate First

Say this

Before the story — what's the rate?

Do this now 4 min

Before evaluating the specifics of your situation, write down: "In cases like this, the usual outcome is ___." Look it up if you can, estimate if you can't. Then ask: what specific evidence justifies deviating?

Use when

You're making a forecast, evaluating risk, or feeling unusually optimistic or pessimistic about an outcome.

Avoid when

The situation is genuinely unprecedented and no meaningful comparison group exists.


Why it works

Humans overweight vivid details and underweight statistical reality — starting with the base rate anchors judgment in evidence rather than narrative.

Your brain is a story machine. Give it a vivid detail — a friend who succeeded, a news headline, a gut feeling — and it will build a confident prediction around that single data point, ignoring the broader pattern entirely. Base rates are boring but brutally accurate: most restaurants fail, most startups fail, most projects take longer than planned. Starting with ‘what usually happens in cases like this’ doesn’t mean obeying statistics blindly. It means using them as a starting position, then asking what specific evidence justifies moving away from them.


Go deeper · 8 min read
Base Rate Neglect: Why Your Brain Ignores Statistics and Trusts Stories
Give your brain a single vivid data point and it will construct an entire forecast around it, ignoring the broader pattern entirely. Base rates are the antidote — boring, unglamorous, and brutally accurate.
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