A lottery is a unique gambling event because it costs only a small amount of money to get a chance to win a very large jackpot, albeit at very long odds. The huge jackpot is the main selling feature of the lottery. Rollover jackpots spur ticket sales. As more people buy tickets, the jackpot grows, while the odds of winning decrease. However, this does not deter ticket sales—sales actually increase under these circumstances. Lottery players often go against the statistical odds, playing in games with large rewards but small probabilities of winning rather than games with small rewards and better probabilities of winning. The lottery lure seems to be that winning a multimillion-dollar jackpot would be life-changing.
Lotteries are successful because people are ignorant of or choose to ignore the laws of probability. For example, the odds of choosing six numbers correctly out of forty-nine are approximately fourteen million to one. Ian Stewart, professor of mathematics at the University of Warwick in Coventry, England, once said that lotto games "are a tribute to public innumeracy" ("It Probably Won't Be You," Times Higher Education Supplement, April 12, 1996).
A 1998 study performed on behalf of European lotteries (Mark D. Griffiths and Richard T. A. Wood, Lottery Gambling and Addiction: An Overview of European Research, European State Lottery and Toto Association, Lausanne, Switzerland, 1999) looked at why people continue to play the lottery despite the long odds. The following reasons were given:
- The lure of a very large jackpot in exchange for a very small investment
- Successful advertising
- Publicity about jackpot winners
- Ignorance of probability theory
- Televised drawings
- Overestimating of positive outcomes and underestimating of negative ones
- The credibility of government backing
- Belief in players' own luck
One of the most interesting theories of the study concerns the role of entrapment in lottery play. Many people select the same numbers week after week. For example, a United Kingdom newspaper reported that 67% of people surveyed chose the same lottery numbers each week, mostly based on birthdates, address numbers, and lucky numbers. As time goes by and their numbers are not selected, these people do not become discouraged. Instead, they think their chances of winning are getting better. This mind-set is called "the gambler's fallacy." It is a common myth that the probability of winning increases the longer a losing streak lasts. Often players experience near-misses, in which two or more of their numbers are drawn during the jackpot drawing. This only convinces them that they are getting closer to the big win. They become increasingly entrapped in playing their numbers and fear skipping even one drawing.
The study also reports on a 1996 survey that found that 22% of respondents believe they will win a lottery jackpot at some point. The lotteries themselves feed the illusion that winning is commonplace by encouraging widespread media coverage of winners and their stories.