2.5 COSMIC FFP and Functional Complexity (FC) Measures: A Study of Their Scales, Units, and Scale Types

Abstract

This paper presents an overview of some measurement concepts across both COSMIC-FFP, an ISO standard (ISO/IEC 19761) for functional size measurement and Functional Complexity (FC), an entropy-based measure. It investigates in particular three metrological properties (scale, unit and scale type) in both of these measurement methods.The COSMIC FFP (Abran and Symons 2005) functional size measurement method was developed by the Common Software Measurement International Consortium (COSMIC), and it has been adopted as an international ISO standard: ISO 1976 (ISO 2003d). COSMIC FFP measures the software functional user requirements and is applicable throughout the development life cycle, right from the requirements phase to the implementation and maintenance phases. This method has been designed to measure the functional size of management information time software, and multilayer systems. Since many of the software systems targeted by the COSMIC FFP method are large-scale and inherently complex, feedback on this complexity would provide additional information to improve its effective management throughout the software life cycle: in Alagar et al.(2000) an entropybased measure of functional complexity has been proposed. This paper presents a study of the scales, units, and scale types of both COSMIC FFP and an entropy-based functional complexity measure. Previous studies have analyzed the scale types of many software measures (eg, Zuse 1991