An important competence of the SD&I group is the design of optimal complex systems based on requirements. It is the art of design itself which is the valuable process. This art cannot be captured by documents or well defined (rigid) processes. Its prime strength comes from ingenuity and creativity of people. Of course, domain knowledge and structure will not harm but it is the art of "doing design" which leads to optimal implementations of complex systems.
As is the case with other sciences, an important process is discussing the problem. In the figure below several phases in the design process are depicted. The art of the design takes place within the yellow zones. We think that the costing process is over rated. After a design implementation is created it should be relatively easy to estimate what a system implementation is going to cost. If this estimate turns out to be too high for a given budget there are only two options:
1. Stick to the original requirements;
2. Relax the original requirements.
In both cases the design implementation which has been costed is wrong and more creative design in the yellow zones is required. In practice however most discussion takes place in the red (wrong) zone.