Approximate COSMIC Size: The Quick/Early Method

The COSMIC method is based on the counting of data movements from/to persistent storage and users. This requires some kind of data analysis to identify data groups. Project managers often need functional size at the beginning of the project life cycle but usually data analysis is not performed in the requirements elicitation phase. Moreover, rapid sizing can be requested since there is insufficient time or resources to apply the standard detailed method. Thus, there is the need of a simplified and rapid COSMIC measurement method to be applied to requirements elicitation documents. Such a method should avoid the use of scale factors since incorrect calibrations of the scale factors can lead to inaccurate approximations. To address the problem we proposed a simplified measurement process (named Quick/Early) that can be applied on the use case models and aims to reduce the measurement time, reaching a trade-off between an accurate measurement and time available. To support the measurement process we proposed a template for use cases that makes the functional components immediately identifiable, i.e., The sequences of events. The application of the method on a case study showed a good accuracy.