3. The biggest danger in playing high-probability games is the risk of overbetting. If you judge that an event has a 70 percent chance of success when in fact it is only a 55 percent event, you run the risk of so-called gambler’s ruin. The way to minimize that risk is to underbet, by using what is known as a half-Kelly or fractional-Kelly model. For example, if the Kelly model would tell you to bet 10 percent of your capital, you might choose to bet only 5 percent (half-Kelly) instead.
