Glossary term
Base Rate
How common something is before you use new evidence about a specific case.
Visual intuition
3 in 100
before new evidence
The highlighted cases show the starting frequency before any new evidence arrives.
Example
If 1 in 1,000 people has a condition, that 1 in 1,000 is the base rate before any test result.
How It Works
The base rate sets the starting . A test result, warning sign, or clue should update those odds, but it does not erase how rare or common the thing was to begin with.
