via The Skeptic’s Dictionary

This scam involves making a series of opposite predictions (on winners in the stock market, football games, or the like) and sending them to different groups of people until one group has seen your perfect track record sufficiently to be duped into paying you for the next “prediction.”

For example, Notre Dame is playing Michigan next week, so you send 100 letters to people, predicting the outcome of the game. It doesn’t really matter whether the recipients of your letter are known to bet on college football games. The information you provide will stimulate some of them to want to bet on the game. You name your letter something swell like The Perfect Gamble. In 50 letters you predict Notre Dame will win. In the other 50 you predict Michigan will win. You write a short introduction explaining that you have a secret surefire method of predicting winners and to prove it you are giving out free predictions this week. Notre Dame wins.

The next week you send a free copy of The Perfect Gamble to the 50 who got the letter that predicted a Notre Dame victory. In the introduction you remind them of last week’s prediction and you inform them how much they would have won had they followed your advice. To show there are no hard feelings and to give them one more chance to take advantage of your surefire system you provide—free of cost—one more prediction. This week Notre Dame is playing Oregon State. You divide your list of recipients and you send 25 letters predicting Notre Dame will win and 25 predicting Oregon State will win.

After the second game, you will have 25 people who have seen you make two correct predictions in a row. Three correct predictions in a row should convince several recipients of your letter that you do have a surefire way to pick winners. You now charge them a substantial fee for the next prediction and, if all goes as planned, you should make a handsome profit even after postage and handling costs.

Since you are a crook for running this scam, you won’t feel guilty in promising the prospective suckers their money back if not completely satisfied with your predictions. Your hope is that they will be greedy and say: “How can I lose?” You needn’t remind them how. You might even be able to rationalize your behavior by telling yourself that they deserve to be scammed because they’re so greedy!

For different audiences, you can pretend to be a psychic or an astrologer or a mathematician or a gambler who knows how to fix college football games. If you are cheating the gullible as well as the greedy, you may be able to convince yourself that you are performing a beneficial service to the community by cheating these people out of their money. You might persuade yourself that rather than try to put you in jail for being a fraudulent scammer, society should give you an award for reminding people to use their common sense and critical thinking skills.

A variant of the perfect prediction scam is used by some psychics. If you tell enough clients “someday you will be rich beyond your wildest dreams,” then if one of them inherits a great sum or wins a lottery, you may get credit for being psychic. (More . . . )