The term “near miss” could be used in any domain where a particularly good (or bad) outcome has—or seems to have—almost occurred. Near misses are commonly pointed to in many casino games, but they are particularly relevant to slot machinesSlot machines, also known as a fruit machines (e.g., in the United Kingdom), pokies (e.g., in Australia), one-armed bandits, or simply slots, are games of... More. This is due, in large part, to the unrepresentative high-frequency of near misses that are intentionally programmed into today’s machines. As such, the discussion here will focus on the near miss in slot machines.
A near miss refers to a situation where the symbols on a slot machine almost align in a winning combination, but not quite, giving the player the impression that they were very close to winning. Near misses were, of course, common even in the day of the mechanical slot machine, when the spinning physical reels accurately conveyed the random nature of the game, since there are many more ways to “nearly win” than there are to actually win. But with today’s machines, the physical reels are controlled by a computer chip and each stop on that reel is mapped to a “virtual reel” that can theoretically have an essentially limitless number of stops, with certain particularly valuable outcomes extremely rare whereas other outcomes can be mapped so as to occur frequently. So long as the stops on the virtual reel are random, such slot machines are legal, at least in casinos in Nevada, despite the fact that the suggestion of randomness is extremely misleading since players are not explicitly informed about the distinction between the physical and virtual reel, the physical reel conveys a perception of randomness mimicking the original mechanical design, and outcome probabilities for the different prizes are not reported.
With the advent of the virtual reel, near misses can be—and have been—intentionally designed to occur more frequently than the perception of chance would suggest (if the structure of the physical reel were the source of the perception of randomness). The blank stops just above and below jackpot symbols, for example, can be and often are mapped so as to occur more often than most other stops on the virtual reel. The jackpot symbol itself, on the other hand, can be mapped so as to be exceedingly uncommon. Since the virtual reel can conceivably be distinct for each of the three or more physical reels on the slot machine, or can refer to the entire combination of all reels, jackpot symbols can occur more often on early reels than later ones, or other creative near-miss combinations can be designed into the game. Since the laws regarding randomness are complicated and are often under-specified given the distinction between the virtual and the physical reel, how free casinos are to select the characteristics of the near miss is largely a matter of speculation and debate. Furthermore, the computer chips can allow functionality that the casino operators are not allowed to use because of legal requirements, but that they can use for activities like promotional slot machine tournaments, including the ability to remotely change the payout schedules of the machines or to have the machines payout jackpots. I have encountered repeated first-hand reports from slot-machine technicians, game designers, and casino managers, along with regular players themselves, suggesting that this happens on a regular basis, but these claims go along with a wide variety of smetimes exceedingly fantastical claims that make it difficult to confidently discern truth from fiction.