The concept of the Technical Design Diagnostic is that it is a first step in getting a handle on the project. If your goal is to find the best design that meets your client's program, including budget and schedule, which it should be, then the Technical Design Diagnostic is the most direct way to do that.
The Technical Design Diagnostic also takes less time than a design study that ignores the parameters that will inevitably bring you back to just a subset of what you once thought was possible. We have found that by using the Technical Design Diagnostic, the project design concept becomes very clear in just a few days for most projects.
The Technical Design Diagnostic is intended to be followed one step after the other in roughly the order shown here. When you have thought all these issues through, then you are ready to start designing.