A Generalized Representation for selected Functional Size Measurement Methods

The management of software cost, development effort and project planning are key aspects of software development. Functional size measurement (FSM) has been proposed as a tool for these management requirements. Function Point Analysis (FPA) can be considered as the first FSM method published. Based on FPA, other methods have been proposed as improvements and alternatives that differ in their respective views on functional size. FPA is an intuitive approach without theoretical foundation, and without a measurement model. It is therefore unclear, what FPA actually measures and what the differences between the FSM methods are. We use an axiomatic approach based on measurement theory to develop a model for existing FSM methods. In this paper, we propose a model as a generalized representation for a set of methods: IFPUG FPA, Mark II FPA, and FFP. This view can be used as a basis for the analysis of FSM methods and for a discussion of their differences.