Approximation of COSMIC functional size to support early effort estimation in Agile

摘要

The demands in the software industry of estimating development effort in the early phases of development are met by measuring software size from user requirements. A large number of companies have adapted themselves with Agile processes, which, although, promise rapid software development, pose a huge burden on the development teams for continual decision making and expert judgement, when estimating the size of the software components to be developed at each iteration. COSMIC, on the other hand, is an ISO/IEC international standard that presents an objective method of measuring the functional size of the software from user requirements. However, its measurement process is not compatible with Agile processes, as COSMIC requires user requirements to be formalised and decomposed at a level of granularity where external interactions with the system are visible to the human measurer. This time-consuming task is avoided by agile processes, leaving it with the only option of quick subjective judgement by human measurers for size measurement that often tends to be erroneous. In this article, we address these issues by presenting an approach to approximate COSMIC functional size from informally written textual requirements demonstrating its applicability in popular agile processes. We also discuss the results of a preliminary experiment studying the feasibility of automating our approach using supervised text mining.