FPA-Based Software Effort Estimation Research And Practice

Software effort estimation plays a significant role in software development projects. It is the basis of project planning and control and ensures the success of projects. With the continuous increasing emphasis on project management, software effort estimation gains more recognition with management and plays more important role in project management.This paper expatiates on the elementary theory of software effort estimation, and analyzes the factors that affect estimation accuracy. Through researching the existing estimation methods and models and analyzing their advantages and disadvantages paper proposes a software estimation method based on organization's historical project benchmarking data, which uses IFPUG FPA as the size measurement method. This method first constructs the relationship between size and effort using historical project benchmarking data, then effort of project being estimated can be derived using its size. In addition, to overcome the difficulties of applying IFPUG FPA in early life cycle when requirement is insufficient, Early&Quick FP, a variant of IFPUG FPA, is adopted. It is further adapted to improve its accuracy in sizing. Further more, the paper proposes a software development life cycle model which inosculates the effort estimation method and rational unified process. Four phases' tasks are carried out: early estimation in inception; effort baseline construction in elaboration; project status tracking and control in construction; data collection and analysis in transition. The data collected will update the project historical benchmarking data and be used to improve estimation model and process. This model overcomes the conflicts between effort estimation method and software development model, and achieves the effective interaction between effort estimation and project management.