关于投资额不等互斥方案经济评价的分析

Economic Evaluation and Analysis on Mutually Exclusive Alternatives of Unequal Investment

从分析绝对量（净现值）与相对量（净现值指数，内部收益率）指标的特性入手，说明两种指标评价投资额不相等的互斥方案的矛盾性是客观存在的。因此，对投资额不等的互斥方案的评价产生两种观点与方法。一种是用净现值指标评价与选择方案，一种是在投资相等的情况下，使用净现值指标，否则要配合使用净现值指数指标或构造满足相等投资额的条件。最后分析指出后一种观点与方法忽略了技术经济评价的一个假设：穷举各种可能的方案，因而是不正确的。

On the basis of analysing the features of absolute amount indicator (NPV)and relative amount indicator (NPV index, IRR), it is indicated that the contradictory of mutually exclusive alternatives (MEA) providing investment amounts are unequal. Hence, there are two kinds of viewpoint and method in evaluating the MEA when investment amounts are unequal. The first uses NPV index to evaluate and alternate. The second uses NPV index when investment amounts are equal, otherwise it's necessary to match NPV index or create the conditions so as to make investment amounts equal. In the end, this paper indicates that the latter viewpoint and method neglecting a hypothesis in technologically economic evaluation, i.e. listing all probable alternatives, are incorrect.