The Architecture Tradeoff Analysis Method (ATAM)

The SEI's Architecture Tradeoff Analysis Method^® (ATAM^®) is the leading method in the area of software architecture evaluation. An evaluation using the ATAM typically takes three to four days and gathers together a trained evaluation team, architects, and representatives of the architecture's various stakeholders. Proven benefits of the ATAM include

• clarified quality attribute requirements
• improved architecture documentation
• documented basis for architectural decisions
• identified risks early in the life-cycle
• increased communication among stakeholders

The following diagram displays a conceptual flow of the ATAM.

Business drivers and the software architecture are elicited from project decision-makers. These are refined into scenarios and the architectural decisions made in support of each one. Analysis of scenarios and decisions results in identification of risks, non-risks, sensitivity points, and tradeoff points in the architecture. Risks are synthesized into a set of risk themes, showing how each one threatens a business driver.

The most important results are improved architectures. The output of an ATAM is an out-brief presentation and/or a written report that includes the major findings of the evaluation. These are typically:

• the architectural styles identified
• a "utility tree" - a hierarchic model of the driving architectural requirements
• the set of scenarios generated and the subset that were mapped onto the architecture
• a set of quality-attribute specific questions that were applied to the architecture and the responses to these questions
• a set of identified risks
• a set of identified non-risks

Additional Information

Read More:

• Evaluating Software Architectures: Methods and Case Studies, by Paul Clements, Rick Kazman, and Mark Klein.

• Len Bass, Robert Nord, William Wood, David Zubrow, Risk Themes Discovered Through Architecture Evaluations (CMU/SEI-2006-TR-012).

• Rick Kazman, Len Bass, Categorizing Business Goals for Software Architectures (CMU/SEI-2005-TR-021).

• Robert L. Nord, James E. Tomayko, Rob Wojcik, Integrating Software-Architecture-Centric Methods into Extreme Programming (XP) (CMU/SEI-2004-TN-036).

• Additional ATAM reports

Products and Services: Learn about ATAM and architecture evaluation and analysis related products and services.

Contact Information: For technical details about ATAM, contact Mark Klein.

Working with the SEI: Learn more about working with the SEI in software architecture.