The Law of Large Numbers: Small Samples Are Wild
Seven heads in ten flips is unremarkable; seventy thousand in a hundred thousand would be extraordinary. The same probability, different room for chance — with consequences most people miss.
Concept
Regression to the Mean
Longevity and Health: The Big Effects Are the Ones Nobody Sells
The interventions with the largest effects have been known for decades and are unglamorous. Attention flows almost inversely to effect size, for a simple reason — the big ones cannot be sold.
The Observer Effect: Measuring Something Touches It
Checking a tyre's pressure lets out a little air, so the reading is never quite what was there before. With objects that hardly matters. With people it can be larger than what you were trying to measure.
Half-Life: Why the Last Bit Takes So Long to Go
An afternoon coffee still has an eighth of its caffeine in you the next morning. Anything that loses a constant proportion per period behaves this way — including skills and knowledge.
The Base Rate Fallacy: Start With How Common It Is
The quiet, bookish stranger sounds like a librarian. There are a hundred times more salespeople — so the shy ones alone outnumber every librarian in the country.
Regression to the Mean: The Jinx That Is Just Arithmetic
Praise a great performance and the next is worse; criticise a bad one and the next improves. A flight instructor learned this lesson over years of observation — and it was never about motivation.