ThinkCritical.eu · Manipulation atlas
Group decisionsBase-rate neglect
A vivid story outweighs the statistics on how similar cases usually turn out.
A vivid story or a convincing detail sticks in the mind far more easily than dry statistics. Yet the statistics – how often something usually works out – are the best starting point for any estimate. Only then should you adjust for the specific circumstances.
A neighbour excitedly tells you his friend opened a café and earned back the investment within a year: “I'm going to try it too.” He doesn't check how many new cafés and restaurants close in their first few years. The success story is true – but nobody tells the failed ones.
How to spot it
- The decision rests on one striking story, not on figures about similar cases.
- Everyone talks about how special our situation is, and nobody asks how things usually turn out.
- Documents with the statistics exist, but nobody has opened them.
- A rare event seems likely because it was in the news recently.
How to check and what to do
- First find the base rate: how many similar cases out of 10 or 100 usually succeed.
- Only then ask how your case demonstrably differs and how much that changes the estimate.
- Look for the failures too, not just the stories people talk about.
- In meetings, start with the documents and numbers, not with impressions.
Tip: When a disease is rare, most positive results even from a very accurate test can be false. That's why doctors confirm a positive result with further tests.
Full explanation and exercises:
thinkcritical.eu/en/manipulation-atlas/base-rate-neglect