For each objective probability ─ from one percent to 100 percent ─ we want to know the subjective probability weight. When we make decisions, do we treat a one-percent chance just like one percent, or like something else? Events that could happen but aren't likely ─ low-probability events ─ can be defined as probabilities up to about 25 percent. Low-probability events tend to factor more into decisions than they should. That is, an event that has an objective one-percent chance of occurring could subjectively seem like it has a five-percent chance of occurring. We overestimate the likelihood of these low-probability events. In general, the smaller the probability, the more we overestimate its likelihood. For example, people who play the lottery are often optimistic about winning. However, the odds of a single ticket winning the largest, most popular U.S. lotteries are on the order of one in 175 million.