Judgment & probability

12 ideas across the corpus

Estimating odds, reading data and avoiding the statistical traps that fool almost everyone.

Humans are terrible intuitive statisticians. We ignore base rates, see patterns in randomness, and mistake a vivid story for a likely one. Pairing the discipline of Bayesian thinking and regression to the mean with an awareness of the gambler’s fallacy and the representativeness heuristic is how you actually reason about an uncertain world.

Key ideas here: Bayesian thinking, Regression to the mean, Expected value, Base-rate neglect, The gambler’s fallacy — and 7 more below.

Mental models

Mental model

Bayesian thinking

Bayesian thinking is updating your beliefs in proportion to new evidence — starting from a prior probability and revising it as data arrives, rather…

Mental model

Regression to the mean

Regression to the mean is the tendency for extreme results to be followed by more average ones, simply because luck evens out. An exceptional…

Mental model

Expected value

Expected value is the average outcome of a decision if you could repeat it many times — each possible result weighted by its probability. It tells you…

Mental model

Signal vs noise

The signal-to-noise model distinguishes meaningful information (signal) from random, irrelevant fluctuation (noise). Most data is mostly noise, and…

Mental model

The black swan

A black swan, in Nassim Taleb’s sense, is a rare event that is a huge surprise, carries enormous impact, and — only afterwards — gets explained as if…

Cognitive biases

Cognitive bias

Base-rate neglect

Base-rate neglect is the tendency to ignore how common or rare something is (the base rate) and judge by specific, vivid details instead. It’s why a…

Cognitive bias

The gambler’s fallacy

The gambler’s fallacy is the belief that past random events change the odds of future ones — that after a run of reds, black is "due." For independent…

Cognitive bias

Representativeness heuristic

The representativeness heuristic is judging the probability of something by how closely it matches a mental prototype, rather than by actual…

Cognitive bias

Clustering illusion

The clustering illusion is the tendency to see patterns, streaks, or clusters in what is actually random data. Genuine randomness produces more…

Cognitive bias

Hot-hand fallacy

The hot-hand fallacy is the belief that someone who has succeeded several times in a row is "on a streak" and more likely to succeed again — even when…

Cognitive bias