Evaluation of Business Software Systems Development and Enhancement Projects Effectiveness and Economic Efficiency on the basis of Functional Size Measurement

Each rational investment decision, also that made by client with regard to the Business Software Systems (BSS) Development and Enhancement Projects (D&EP), should meet two measurable criteria: of effectiveness and of economic efficiency. In the case of BSS D&EP the assumption concerning measurability of these criteria is often treated as controversial. Thus the paper aims at proving from theoretical perspective the capabilities of using the so-called concept of BSS D&EP Functional Assessment (FA), proposed by the author and already verified in practice, based on Functional Size Measurement (FSM) concept and methods, in the area of ex ante and ex post quantitative evaluation of these two criteria. By linking the FSM issues with economic aspects it may contribute to better understanding of the FSM importance, still being underestimated by business managers. Meanwhile, BSS D&EP FA can constitute the basis for rational decisions not only for BSS providers, but also for clients. These issues classify into economics problems of Software Engineering Research and Practice