The quality assurance of dimensions with asymmetric tolerances is as important as for dimensions with symmetric tolerances. A number of methods for calculating corrected capability indices for dimensions with asymmetric tolerances have been suggested, of which all but one involves reassigning the tolerances to become symmetric. As tolerances should be specified in the design phase, not the quality assurance phase the logic of this is flawed. The methods suggested in this article result in the same values for corrected capability as the previously suggested method that does not change the tolerances. This does not mean that one of the two methods are redundant; depending on preference and to some degree the form the data is presented in suggest one is preferred over the other. This article explains how the method suggested was derived and validates the result with computer generated data.

具有非对称公差的尺寸的质量保证与具有对称公差的尺寸一样重要。已经提出了许多计算具有不对称公差的尺寸的校正的能力指数的方法，除一种方法外，所有方法都涉及重新分配公差以使其对称。由于应在设计阶段而不是质量保证阶段指定公差，因此其逻辑存在缺陷。本文建议的方法所得到的校正能力值与先前建议的不会改变公差的方法相同。这并不意味着这两种方法之一是多余的。根据偏好，并在某种程度上以数据的形式显示，建议一个比另一个优先。