本文主旨在介紹益本分析法應用於實際評估中的關鍵因素。益本分析法係彌補市場機能之不足而為社會利益與社會成本的考慮，用以分配資源與所得分配。一份採用益本分析法的可行性分析必須包括下列五項目：（1）成本與收益項目的確定，不可遺漏任何一項。（2）成本與收益的衡量，儘可能量化與貨幣化，須同時採用市場價格及影子價格。（3）計畫的有效期限與收益的發生時期對益本比有深遠的影響。（4）折扣率是將未來的收益與計畫的營運成本折算成現值，以總淨收益（收益減計畫營運成本）與總投資作比較，判定可行與否，益本比至少須大於一。（5）價格水準之取用，即收益與成本均定於某一年或三年之平均價格，因為益本分析法是“有”與“無”計畫真實價格的比較且是事前的分析（Ex. Ante），絕不是“前”與“後”的比較。益本分析法有其限制，例如是部分分析、是中立的，是經濟分析方法之一種但不是目的等。目前廣泛的應用，遭遇到很多經濟分析上的問題。
This paper aims to introduce the application of major components of benefit-cost analysis (B-C analysis) of development projects. The five major components are: (1) thorough identification of as many costs and benefits as many as possible; (2) quantification and monetization of costs and benefits as thoroughly as possible, using both market prices and shadow prices; (3) consideration of economic life of the project, including both long-term and short-term facilities; (4) selection of discount rate to convert the stream of future benefits and operation and maintenance costs of the project to present worth in comparison with the initial investment (usually the most difficult task); and (5) adoption of price level for a certain year to make a comparison of benefits and costs in real terms. The criteria for the selection of a project are: (1) benefit-cost ratio; (2) maximum of net benefits; and (3) internal rate of return of the project. B-C analysis is viewed either for the whole society or at the administrative level only, and comparison is between ”with” and ”without” the project and on ex ante analysis, which is another economic analysis for improving decision-making, as well as a partial equilibrium analysis and neutral in nature.
