9.1 Introduction to Impact Estimation

Systems engineers and managers need a reliable way of analyzing how effective their design ideas or strategies are in meeting the requirements. Surprisingly, there are few methods being taught or used to do this. Impact Estimation (IE) is one of these methods. It is the only one that attempts to use any quantified rigor.

The intention of IE is that it helps answer the question of how our design ideas impact all a system's critical performance attributes (such as usability and reliability) and all its resource budgets (such as the financial cost and staff headcount) for implementation and operational running. This question is fundamental to systems engineering.

IE can be used for a wide variety of project purposes. Its most important uses include:

• Comparing alternative design ideas: "What's best?"

• Estimating the state of the overall design architecture: "Have we designed enough?"

• Analyzing risk: "Where are our biggest problems now?"

• Planning and controlling evolutionary project delivery steps: "Is the project on track?"

IE can be used at any organizational level and by different specialist staff roles (such as systems analyst, architect, risk analyst, project manager and purchasing manager) to evaluate any technical or organizational idea. In fact, IE is useful in permitting integrated assessment of technical and organizational design ideas. It is specifically helpful in improving communication about system design decisions across organizational levels and boundaries.