Function Point Analysis

Function Point Analysis (FPA) is a method for measuring the functional size of a software system. The rules governing FPA are laid down in the Counting Practices Manual (the CPM) by the International Function Point Users Group. This paper ◊ defines a formal notation (N) for software designs, ◊ shows that the notation N is consistent with the language of the the CPM ◊ shows that FPA can be expressed as a program (P) operating on a design expressed in N ◊ shows that the program P can be expressed in 17 steps of which 12 are algorithmic and five require human judgment. Each step of the argument is justified by reference to the the CPM. The notation N is consistent with that used by many CASE tools. The paper is designed for two classes of reader, the function points expert and the tool builder. For the function points expert it captures the mechanism of counting function points as defined in the CPM; for the tool builder it provides the detail required to start building the physical design of an interactive tool for counting function points.