增量分析的原理及其在项目评估中的应用

增量分析技术是工程项目评估中的一项重要技术,但是其经济原理和使用范围尚未得到完全分析.增量分析考察不同方案间成本和收益的差异,其经济原理即为边际分析.使用增量分析技术时沉没成本和机会成本的概念在交替和重复使用.增量分析可应用于价值工程分析,或一系列的无限型方案,并可解决不同分析工具引起的方案排序不同的困境.文中给出了三个方面的实例以说明增量分析技术的应用,即增量分析在价值工程和一系列的无限型方案中的应用,以及用于解决不同分析工具引起的方案排序不同的困境时的应用.对比净现值技术,增量分析对项目的评估结果与净现值法相同,但更富于逻辑性且易于理解.另外,增量技术不仅适用于基数尺度为单位如货币等指标表示的项目,也可适用于以序数尺度为单位表示的项目,如功能、效果或效用等,以分析效果成本比或效用成本比等.因此,项目评估中建议增量分析技术优先采用.

The Principle of Incremental Analysis and its Application in Project Appraisal

The Incremental Analysis(IA) is one of the important techniques for project appraisal,and yet its rationale and applications are not perfectly analyzed by the analysts.IA can be defined as the examination of the differences between alternatives,and the concepts of sunk cost and opportunity cost are alternately and repeatedly adopted during IA,which is one of marginal analyses.For its applications,we give three examples,e.g.in the application of Value Engineering(VE),a series of unlimited alternatives,and appraisal dilemmas using different tools.In IA we select the best alternative the same as the result when we use the NPV method,but contrary to the NPV method,IA is a logic tool and easy to understand.Moreover,IA can not only be used to evaluate alternatives indicated by cardinal units such as money,etc.but also ordinal units such as function,effectiveness or utility,in order to analyze the Effectiveness-cost Ratio and Utility-cost Ratio.So,IA should be adopted firstly in investment analysis,particularly used separately to appraisal the projects.