Overconfidence effect

What it is

Being more certain of our judgments, knowledge and forecasts than their accuracy justifies.

Example Experts who say they are "90% sure" and turn out to be right about 70% of the time.

Hindsight bias bias
Believing the past was predictable makes us overconfident about predicting the future.
Groupthink bias
Groups reinforce each other's confidence and feel invulnerable.
Optimism bias bias
Overconfidence is about how right we are; optimism bias is about how well things will go for us.
Planning fallacy bias
The planning fallacy is overconfidence applied to our own schedules and budgets.
Bias blind spot bias
Believing ourselves less biased than others is itself overconfidence.
Dunning-Kruger effect bias
Novices' inflated self-assessments are a special case of overconfidence.
Excessive self-regard tendency bias
Munger's excessive self-regard is the root of overconfidence about ourselves.
Illusion of control bias
Believing we control outcomes feeds confidence in our predictions.
What you see is all there is bias
A coherent story built from limited information breeds confidence, which has little to do with how complete the information is.
Black swan events bias
Tight forecasts leave no room for the rare large surprise.
Domain dependence bias
Skill in one domain breeds confidence that carries over to others where it doesn't apply.
Forecast illusion bias
Precise forecasts reflect confidence rather than accuracy.
Winner's curse bias
The winner of an auction is the most overoptimistic bidder.
Drug-misinfluence tendency bias
Alcohol in particular inflates confidence.