Validation of the robustness of the selection of the preferred design concept through a comprehensive sensitivity analysis

The selection of the preferred design concept is a crucial step in the systems engineering framework. After the identified need or opportunity has been translated into stakeholder requirements, and after as many as possible potential solutions or design concepts have been identified, the optimum one is to be selected. The traditional approach is to choose the design concept that promises to result in the system that better meets the stated requirements. The problem is that frequently the selection is not confirmed to be robust, which eventually means that the system will not achieve the effectiveness desired by the customer. This paper proposes a comprehensive sensitivity analysis to ensure the robustness of the selected design concept. The selection is normally made with the aid of mathematical models, whose inputs are subjective and/or just reasonably accurate predictions. Ensuring that the output of the model is not affected by reasonable changes in the inputs is essential, yet this aspect is far too often neglected because of lack of awareness of its importance or even because of knowledge on how to actually do it. This paper stresses the importance of rightly conducting this so critical step in the systems engineering framework and shows a four-step approach to performing a comprehensive sensitivity analysis. A simple example is presented to illustrate the proposed approach.