Consider that in this particular case, you’re seeing only those letters he chose to send you—you’re not seeing the letters he sent to anyone else. Statisticians call this selective windowing. The case I’m describing actually occurred, and the broker was imprisoned for fraud. At the beginning of the whole scheme, he sent out two sets of letters: One thousand people received a letter predicting that IBM stock would go up, and one thousand received a letter predicting that it would go down.
