A 99% accurate test comes back positive. Most people assume they're 99% likely to have the disease. The real answer is closer to 9% — and the math is easier than it looks.
A dollar next year isn't worth a dollar today. Discount rates, NPV, and the surprisingly emotional math of decisions that play out over time.
An unweighted pros-and-cons list rewards whoever can think of the most reasons, not whoever has the most important ones. Here's how to fix it.
A positive expected value doesn't mean you'll win on the first try. Here's how to tell whether one shot is enough — or whether you need to keep swinging.
The decisions with the highest expected value often feel the most terrifying. Here's why that's actually good news.
Your gut isn't irrational — it's doing expected value math, just badly. Here's how to do it well.
