A Report on Using Simplified Function Point Measurement Processes

Background: Function Point Analysis is widely used, especially to quantify the size of applications in the early stages of development, when effort estimates are needed. However, the measurement process is often too long or too expensive or requires more knowledge than available when development effort estimates are due. To overcome these problems, simplified methods have been proposed to measure Function Points. Objectives: The work reported here concerns the experimentation of simplified functional size measurement methods in the sizing of both “traditional” and real-time applications. The goal is to evaluate the accuracy of the sizing with respect to full-fledged Function Point Analysis. Method: A set of projects, which had already been measured by means of Function Point Analysis, have been measured using the NESMA and Early&Quick Function Points simplified processes: the resulting size measures were compared. Results: while NESMA indicative method appears to quite overestimate the size of the considered applications, the other methods provide much more accurate estimates of functional size. EQFP methods proved more accurate in estimating the size of non Real-Time applications, while the NESMA estimated method proved fairly good in estimating both Real-Time and non Real-Time applications. Conclusions: The results of the experiment reported here show that in general it is possible to size software via simplified measurement processes with an acceptable accuracy. In particular, the simplification of the measurement process allows the measurer to skip the function weighting phases, which are usually expensive, since they require a thorough analysis of the internals of both data and operations.