Image Theory in Integrated Product and Processs Design

Abstract

There is emerging appreciation from the engineering community that decisionmaking is fundamental to the success of Integrated Product and Process Design (hereafter IPPD). Most methods focus on improving design decisions by providing information about the needs of downstream development and life-cycle stages. More recently, efforts have also been made to improve design decisions through the use of formal decision analysis techniques such as Game Theory, Utility Theory and the Analytical Hierarchy Process. However, the decisions taken in IPPD invariably involve multiple stakeholders and product lifecycle stages, which ArrowÆs Impossibility Theorem demonstrates cannot be accommodated in a mathematical algorithm. The reduction of design decision-making to a numerical problem is open to other criticisms, the result is dependent upon the decision analysis technique used and the social aspects of the design process are not accommodated. Negotiation is often needed to align the perspectives of different designers, and there is a need for communication between product development functions so that designers can understand how their decisions affect downstream perspectives. This paper presents the early stages of research to define an alternative approach to design decision-making based on a naturalistic decision analysis technique known as Image Theory. This approach is not intended to replace normative decision analysis, but to support it by providing a framework for identifying conflicts between perspectives, where negotiation is needed to develop a shared point of view. This is used to build up a Choice Set that is mutually acceptable to both product and process design, from which an option can be selected using normative decision analysis. The use of this method is illustrated with a case study, and future work needed to refine the framework is discussed.