A mapping model for assessing project effort from requirements

Since the effort required to develop a system depends on its requirements, it is important to consider the resulting effort when deciding on the requirements. Miscalculating the effort may lead to requirements that cannot be implemented within given budget constraints. In order to support requirements engineers in calculating the effort resulting from the requirements they elaborate correctly, we develop a mapping model for assessing project effort from requirements (MMAPER) in this paper. MMAPER incorporates effort estimation into requirements engineering and thereby enables engineers to proactively assess project effort without demanding that they spend significant additional time on this task. MMAPER measures system size using function point analysis and assesses the resulting effort using the Constructive Cost Model 2. The theoretical underpinning of the methods stems from theoretical perspectives from which we derive theories of how requirements determine the resulting project effort. We also take into consideration that it is important to distinguish requirements of different size but also implemented in different contexts for estimating the resulting effort. We empirically evaluate the model using data from five case studies which we conducted with a financial services organization. The developed model provides very accurate effort estimations, across both controlled experiments and field applications.