Harmonising software engineering and systems engineering cost estimation

Abstract

Complex systems are developed with the help of numerous engineering disciplines. In software-intensive systems, software and systems engineers play a major role in design, development, test and deployment. Since these roles are often very tightly coupled, it is difficult to determine which life cycle functions can be performed jointly versus separately. This makes it particularly difficult for resource estimation and project planning. To resolve this issue, we examine the gaps and overlaps between software engineering and systems engineering cost models with intent to harmonise the estimates for project estimation. In particular, we evaluate the central assumptions of the constructive cost model II and constructive systems engineering cost model and propose an approach to identify gaps and overlaps between them. Furthermore, we provide guidelines on how to reconcile and resolve the identified gaps and overlaps. The ultimate purpose of this work is to develop effective techniques for accurately estimating the combined software and systems engineering effort for software-intensive systems.

Keywords:

• cost estimation
• software engineering
• COCOMO II
• systems engineering
• COSYSMO

Acknowledgements

Many of the results presented have benefitted from inputs of subject matter experts who participated in the COSYSMO Workshop at the University of Southern California in March 2008 in Los Angeles, CA, and the Practical Software & Systems Measurement workshop in July 2008 in Mystic, CT.