Lottery is popular and widespread, with 60% of adult Americans reporting playing at least once a year. Each state lottery commission legislates its monopoly; hires or contracts a private firm to run the games; starts with a small number of relatively simple games; and progressively expands its offerings as revenue grows, especially by introducing new types of games such as video poker and keno. The expansion has led to the development of large specific constituencies, including convenience store operators (who are usually lottery vendors); suppliers of instant tickets and scratch-off cards (who frequently contribute to state political campaigns); teachers (in states where a portion of lottery proceeds is earmarked for education); and of course, committed gamblers who spend substantial shares of their incomes on tickets.

One of the messages that lottery marketers rely on is that winning money in the lottery is good for your state, because it supposedly reduces the amount that you would have had to raise through taxes for government programs such as schools and public welfare. However, critics charge that the earmarking of lottery revenues to specific purposes simply reduces the appropriations from the general fund that would have otherwise been made for those programs, and does not result in any increase in overall spending for them.

Random chance plays a significant role in lottery results, but it also depends on the choices that players make about their numbers. Some numbers are more popular than others, and many people choose numbers that are grouped together, such as those that begin or end with the same digit. This tends to decrease the chances of winning, because the same patterns are likely to be chosen by other players.