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File 03The Average Is a Liar

The Average Is a Liar

A bet you win on paper and lose in life.

A friendly coin: heads your money grows by half, tails it shrinks by less. On average it pays — so the brochure says take it. Play your own $100 and watch it sink anyway, then run ten thousand lives at once and see the trick: a tiny handful get spectacularly rich, drag the average up, and the typical player is quietly wiped out. The number everyone quotes belongs to the crowd. The loss belongs to you.

Interactivethe average is a liarrun 10,000 lives

A coin. Heads, your money grows by a lot. Tails, it shrinks by less than it grew. So on average every flip pays — the brochure is not lying about that. Play it for real, round after round, and watch what happens to you.

The crowd’s average

+5.0%

per round — what a brochure quotes

Your own pile, over time

-5.1%

per round — what one life actually compounds

Same coin, two numbers — and the gap between them is the whole trick. One good round and one bad one, a +50% then a −40%, leave you with 90¢ on the dollar. Two ‘average’ rounds, and you are already behind.

Free money on paper.

broke in practice.

Part two — a different lie

“The odds are on my side.”

The average is not the only number that lies. Here is a cousin. Suppose one bad outcome would wipe you out, and each single time you take the risk, the chance of that is tiny. Tiny odds, taken often enough, stop being tiny.

chance you are wiped out at least once63%

The odds are on my side.

they only have to land once.