A gambling game in which tickets are sold and prizes drawn at random. In some countries, the term also refers to a system of allocation of public funds that relies on chance. It is not to be confused with a raffle, a drawing of lots to determine ownership or other rights or with a sports contest in which skill plays an important role.

Lotteries have been around for centuries, but modern state-sponsored lotteries emerged in the United States in the late 1970s. Most states now operate a lottery or a series of lotteries, raising billions each year for such purposes as education and public works projects.

In addition to state lotteries, many private organizations run lotteries. These include nonprofit groups (such as churches and fraternal organizations), restaurants, service stations, bars, bowling alleys, and newsstands. Many of these retail outlets also sell lottery tickets on-line. In 2003, there were approximately 186,000 retailers selling lottery products in the United States.

Most people play the lottery because they think it offers a high potential return for low risk. The prize money is usually quite large, and many players expect to win at some point. Some people play the lottery as a way of saving for college tuition, retirement, or a home, while others view it as an opportunity to avoid paying taxes.

The economics of the lottery are complex. Lottery players contribute billions to government receipts every year, even though the chances of winning are very small. Moreover, the purchase of lottery tickets diverts resources that could be used for other purposes. For example, Americans spend more than $80 billion a year on lotteries; the proceeds could be better spent building emergency savings or paying down credit card debt.

While the economics of the lottery are complex, a basic principle is that the probability of winning is independent of the number of tickets purchased. In other words, if the number of tickets sold is doubled, the probability of winning remains the same. However, if the ticket prices are doubled, the total revenue will increase by an amount equal to the ticket sales.

Lottery operations are a classic case of public policy being developed piecemeal and incrementally, with few if any overall policies in place. Consequently, critics focus on specific features of lottery operations, such as problems of compulsive gambling and alleged regressive impacts on lower-income communities. Nevertheless, these criticisms both reflect and drive the continuing evolution of lottery policies.