What comes to mind

Availability makes a vivid case feel common. Train delays you remember, or a headline that says a risk was halved, crowd out the dull record. Halving a risk that was already two in a thousand is a real change and a small one. The ease of the story is not the size of the risk. When a single example arrives quickly, ask what the published rate says, and whether the headline is a relative change or an absolute one. The bias card names the habit.

Cognitive bias

Availability bias

Availability bias judges how common something is by how easily examples come to mind. Vivid, recent, or personal cases feel frequent. A dull record of ordinary cases is harder to recall and gets underweighted.

Open the full card

Mini check

You remember dramatic train delays and start to believe delays are very common, though the published record shows they are rare. Which bias is this?

Availability: vivid delays are easier to recall, so they feel common.Sunk cost: the trips continue only because the fare was already paid.Anchoring: the first number you heard is dominating the judgement.Halo: one pleasant trait is colouring every other judgement.

A headline says a pill "halves the risk of heart attack". In the trial, risk fell from 2 in 1,000 people to 1 in 1,000. What is the drop in absolute risk?

One person in every 1,000, which is 0.1 percentage points.Half of everyone who takes it is protected from a heart attack.Fifty people in every 100 avoid a heart attack.Nothing at all, because a relative figure cannot be true.

Try it today

The next vivid risk you hear, ask whether you remember it because it is common or because it was loud.

Next step