A lottery is an arrangement in which prizes are allocated by a process that relies wholly on chance. A prize may be a cash sum, goods or services, or even a right to participate in another lottery with the same chance of winning. There are many different types of lotteries, including state-run and commercial lotteries, and private lotteries for housing units or kindergarten placements. Lotteries are an important source of revenue for many states.
Most state lotteries began in the immediate post-World War II period, and their principal argument was that they could expand state spending without imposing excessive burdens on middle-class or working-class taxpayers, because the lottery would generate enough money to pay for everything a state wanted to do. But that dynamic has changed, and today, lotteries are often criticised for their impact on compulsive gambling and their regressive effects on lower-income communities.
The key feature of all lotteries is the drawing, a procedure for selecting winners that involves thoroughly mixing the tickets or other symbols and then selecting them by chance. It is usually done by hand, but with increasing frequency, computer-based procedures are used to mix the tickets and generate random selections.
Many, but not all, lotteries make available the results of their draws after they have closed. Those results typically include the total number of entries, demand information and the breakdown of successful applicants by various criteria. Some, such as the UK National Lottery, also provide details of the prizes awarded.