The ATAM process if a facilitated interaction between stakeholders leading to the identification of risks, non-risks, sensitivities and trade-offs.
Sensitivity Points – a property of one or more components that is critical for achieving a particular quality attribute response. Example – queue depth is a sensitivity point. Changing this can help scalability or/and throughput.
Trade off – is a property that affects more than one attribute. E.g. Having a queue that is persistent or non-persistent impacts durability, availability and throughput. This is a trade-off.
The following model shows Business Drivers to Scenarios decoupled from Architectural Plan to Architectural Decisions.
See Conceptual Model here: http://www.sei.cmu.edu/architecture/tools/evaluate/atam.cfm
In practice, Architectural Approaches is where QARs tagged to distinct approaches are derived from the plan. So you take the plan/presentation à Architectural Approaches à Quality Attributes à Architectural Decisions is probably more accurate.
Advice: Never do Phase 1 and Phase 2 in the same week. Give yourself 1-2 weeks in between.
