A preliminary model of design as a sequential decision process

This paper presents a formal model of design as a sequential decision process. In the process model, the design process takes discrete steps through a space defined by the extent of the set of designs under consideration, the level of detail of the designs, and the level of fidelity of the analyses the designs are subjected to. At the start the design space is broad, the design detail is low, and the analyses are conceptual. The process finishes with a single point design of full detail subjected to the highest fidelity analyses. Two premises underlie the model; first, that design decision making is a process of simultaneously constructing one's preferences while satisfying them. Second, that design using computational models is a sequential process that starts with low fidelity models for initial trades and progresses through models of increasing detail. These premises are supported by research from the domains of behavioral economics, psychology, judgment and decision making, neuroeconomics, marketing, and engineering design, and are substantiated by the authors' own experience. The paper summarizes the pertinent literature, synthesizes a preliminary model of the sequential process and how lower fidelity models couple to higher ones, and develops an experimental case study now being used to exercise the model.