Each rational investment decision, including those made by clients with regard to Business Software Systems (BSS) Development and Enhancement Projects (D&EP), should meet two measurable criteria: effectiveness and economic efficiency. However, in the case of BSS D&EP, the assumption concerning the measurability of these criteria is often treated as controversial. Meanwhile, the so-called concept of BSS D&EP Functional Assessment (FA), proposed by the author and verified in practice, allows for using the potential offered by the Functional Size Measurement (FSM) concept and methods in the area of the quantitative evaluation of these two criteria. Thus, the paper aims at presenting and proving the capabilities of using the functional assessment concept in the quantitative evaluation of BSS D&EP effectiveness and economic efficiency. Linking FSM issues with managerial aspects through the FA concept may contribute to a better understanding of the FSM importance, which is still underestimated by business managers, as in the subject literature this issue is usually considered from a technical perspective. Meanwhile, BSS D&EP FA can constitute the basis for rational decisions not only for BSS providers, but also for BSS clients. These issues classify into economics problems of software engineering research and practice.
The Economic Importance of Business Software Systems Functional Size Measurement
