Gambler's conceit

Gambler's conceit is defined by economist David Ewing as the mistaken belief that one will be able to stop performing a winning action while one continues to win. This belief frequently arises during games of chance, such as casino games, or stock market trading. The individual believes they will be a winner at the game, and able to avoid gambler's ruin, by exerting the self-control necessary to stop playing while ahead in winnings. This is frequently expressed as "I'll stop when I'm ahead." This is irrational since the action contributing to the winning situation (playing) is continuing to produce the desired result and further is being rewarded.

However, since most casino games have a house edge, and if the individual is winning in such a game, he does in fact "beat the house" if he leaves. If said gambler were to continue betting then he would succumb to gambler's ruin. Eventually he would lose all his money, so by quitting the game, he is taking money out of the game which was the house's and is statistically favored for the house to win back. This situation can be seen in the Martin Scorsese movie Casino where Robert De Niro's character makes sure that a high stakes gambler continues to gamble to ensure that the money he won goes back to the casino.

Once in the throes of a winning streak the individual may become convinced that it is their skill, not blind chance, causing their winnings, or good luck on their side, and thus it seems be senseless to stop while still continuing to win. The gambler's conceit is frequently paired with the gambler's fallacy, convincing losing players that it is necessary to continue playing because their luck must soon turn accordingly.