ジェームズ・P・オショネシーが分析した手法はWhat Work on Wall StreetじゃなくてWhat Used to Work on Wall Streetだ、と論じた後、Foolish Fourというすごく怪しい方法を取り上げて次のように言う。

The Foolish Four, in short, was one of the most cockamamie stock-picking formulas ever concocted. The Fools made the same mistake as O’Shaughnessy: If you look at a large quantity of data long enough, a huge number of patterns will emerge―if only by chance. By random luck alone, the companies that produce above-average stock returns will have plenty of things in common. But unless those factors cause the stocks to outper-forms, they can’t be used to predict future returns.
―The Intelligent Investor, Commentary on Chapter 1

過去のデータから未来を予測するんじゃないよ、との教え。

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