Functional Complexity Measurement: Proposals and Evaluations

Several definitions of measures that aim at representing the size of software requirements are currently available. These measures have gained a quite relevant role, since they are one of the few types of objective data upon which effort estimation can be based. However, traditional Functional Size Measures do not take into account the amount and complexity of elaboration required, concentrating instead on the amount of data accessed or moved. This is a problem, when it comes to effort estimation, since the amount and complexity of the required data elaboration affect the implementation effort, but are not adequately represented by the current measures, including the standardized ones. Recently, a few approaches to measuring aspects of user requirements that are supposed to be related with functional complexity and/or data elaboration have been proposed by researchers. The authors of this paper have also proposed a measure of the functional complexity as specified in user requirements. In this paper we take into consideration some of these proposed measures and compare them with respect to their ability to predict the development effort, especially when used in combination with COSMIC measures of functional size