Using the PRiM method to Evaluate Requirements Models with COSMIC-FFP

The COSMIC-FFP is a standard method that has been proven effective for measuring the functional size of business applications and realtime software systems from their functional user requirements specification. Despite of this, the methods based on COSMIC-FFP usually require a mapping between the concepts in the requirements specification and their own terms and do not take into account non-functional requirements. On the other hand, PRiM is a method that aims at assessing non-functional properties at the early stages of the development process. PRiM uses the i* framework to model the functional and non-functional requirements in terms of actors and dependencies among them. In this paper we present how the i* constructs proposed in PRiM can be adapted to measure the functional size using COSMIC-FFP and, as PRiM works with requirements and allows the evaluation of non-functional properties, there is a remarkable benefit when using both methods altogether.