A validation of the component-based method for software size estimation

Abstract

Estimation of software size is a crucial activity among the tasks of software management. Work planning and subsequent estimations of the effort required are made based on the estimate of the size of the software product. Software size can be measured in several ways: lines of code (LOC) is a common measure and is usually one of the independent variables in equations for estimating several methods for estimating the final LOC count of a software system in the early stages. We report the results of the validation of the component-based method (initially proposed by Verner and Tate, 1988) for software sizing. This was done through the analysis of 46 projects involving more than 100,000 LOC of a fourth-generation language. We present several conclusions concerning the predictive capabilities of the method. We observed that the component-based method behaves reasonably, although not as well as expected for "global" methods such as Mark II function points for software size prediction. The main factor observed that affects the performance is the type of component.