巴菲特股东信 1993 年

Academics, however, like to define investment “risk” differently, averring that it is the relative volatility of a stock or portfolio of stocks - that is, their volatility as compared to that of a large universe of stocks. Employing data bases and statistical skills, these academics compute with precision the “beta” of a stock - its relative volatility in the past - and then build arcane investment and capital-allocation theories around this calculation. In their hunger for a single statistic to measure risk, however, they forget a fundamental principle: It is better to be approximately right than precisely wrong.

然而学术界喜欢用另一种方式定义「风险」。他们主张,风险就是一个股票(或一组投资组合)在过去的相对波动。用数据和统计学方法,他们针对每个股票计算出来一个准确的「贝塔系数」,并基于这个计算,建立起晦涩复杂的投资和资产配置的理论。尽管他们亟愿用一个简单的统计学系数来测量风险,他们遗忘了一个基础的原则:模糊的正确比精确的错误要好