Fundamentals of Software Architecture, 2nd Edition

Chapter 22. Analyzing Architecture Risk

Every architecture comes with risks: some operational (such as availability, scalability, and data integrity), some structural (such as static coupling between logical components). Analyzing architecture risk is one of architects’ most important activities, allowing them to address deficiencies and structural decay within the architecture and take corrective action. In this chapter, we show you some key techniques and practices for quantifying, assessing, and identifying risk, and introduce an activity called risk storming.

Risk Matrix

The first thing to determine in assessing architecture risk is its level: whether risk to a particular part of the architecture is low, medium, or high. The challenge here is that assessing risk can be subjective. One architect might hold the opinion that some aspect of the architecture is high risk, while another architect’s opinion might be that the same aspect is medium risk. We italicize opinion here to emphasize the subjectivity of assessing risk. Fortunately, architects have a useful risk-assessment matrix that helps us make risk more measurable.

The architecture risk-assessment matrix (Figure 22-1) uses two dimensions to qualify risk: the overall impact of the risk involved and the likelihood of that risk occurring. The architect rates each dimension as low (1), medium (2), or high (3), then multiplies the numbers within each intersection of the matrix. This provides a numerical representation of risk, ...