"We do not measure the progress of our investments by what their market prices do during any given year. Rather, we evaluate their performance by the two methods we apply to the businesses we own. The first test is improvement in earnings, with our making due allowance for industry conditions.The second test, more subjective, is whether their “moats” – ametaphor for the superiorities they possess that make life difficult for their competitors – have widened during the year."             

—2007 Letter to the Shareholders of BerkshireHathaway

在2007年至股东的信中，巴菲特如此解释衡量企业成功的标准：

“我们不用企业股票在任何一年的市场价格的表现来衡量我们投资的进展。然而，我们用衡量我们拥有的公司的两种方法来评估企业的表现。第一个测试就是盈利的改善，当然我们会考虑行业的情况。第二个测试更主观，就是他们的‘护城河’——比喻让竞争对手日子难过的优势——在这一年里得到了加宽。”

这两个标准，一个短期，一个长期；一个数字量化，一个主观判断，完美的衡量了一个企业。