Experience of combining qualitative and quantitative analysis methods for evaluating software architecture

ATAM helps stakeholders determine where the risks and tradeoffs exist in elicited architectural strategies. But it provides no guidance for understanding economic benefits, thus needs to be complemented by some quantitative approach. CBAM helps software architects consider the return-on-investment of any architectural decision and provides guidance on the economic tradeoffs involved. This paper presents our experience of applying ATAM to a small-scale studio project and analyzes how properly it was adjusted to the project situation, what was done well and what could have done better. This paper also presents a CBAM evaluation for the same studio project that was conducted on the output of the ATAM process. The objective of this evaluation is to justify our decision for .Net over J2EE for the architectural framework for the target software system. Though the evaluation have been performed with several restrictions and assumptions, the experience shows that application of economics technique can effectively complement the ad-hoc qualitative approach such as ATAM by providing disciplined process to frame and structure the qualitative output produced by ATAM.