Illusion of validity
The illusion of validity is overconfidence in a judgment when the available information tells a neat, consistent story, even if that information predicts poorly. The feeling of certainty comes from how well the story hangs together and says little about accuracy.
In everyday life
A hiring manager feels certain about a candidate after one smooth, friendly interview, though casual interviews are a weak guide to how someone will do on the job.
After reading a company's glossy annual report, you feel completely sure its share price will rise, even though you know that experts reading the same reports rarely beat the market.
Why your mind does this
Our ancestors survived by spotting patterns fast: rustling grass might mean a predator, and dark clouds meant rain. Filling gaps with a plausible story lets us act on thin information instead of freezing. A brain that sometimes sees a pattern that isn't there loses less than one that misses a real threat.
Its family, in 30 seconds: Stories & patterns
How to spot it
Ask whether your confidence comes from a good track record or just from the story feeling tidy.
How to counter it
Check how often predictions of this type have actually come true before trusting your gut.