Regression to the Mean
Chapter summary from Thinking, Fast and Slow by Daniel Kahneman.
Extreme performances tend to be followed by less extreme ones. This is not fate, punishment, or reward. It is regression to the mean.
The mind resists this because it craves causality. After a peak, the next result looks like decline that needs explanation. After a disaster, the next result looks like improvement caused by intervention.
Regression creates powerful illusions in coaching, management, and evaluation. You praise after a slump and see improvement; you scold after a peak and see decline.
The slow system can understand regression, but intuition keeps misreading it as a response to what you just did.
If you want to judge interventions, separate trend from noise. Do not let natural reversion masquerade as proof that your reward or punishment “worked.”
A 30-second summary — and that's the point. Read Stacks chapters are deliberately short. The full Thinking, Fast and Slow edition has the examples, the longer argument, and the moments worth re-reading. If this resonated, the Bookshop link below supports the author and an indie bookstore.
Thinking, Fast and Slow is part of this curated reading path — each pairing it with 3 other books that sharpen the same idea: