The decision-based design community has made impressive progress over the past 20 years. The theory has become better founded. Industrial test-bed applications have grown more sophisticated. The successes and failures of methodologies in the field have informed the research agenda. Our interdisciplinary approach has evolved from that of a dilettante to that of a highly skilled systems analyst—one with a deep understanding of the integration of one or more technical specialties. The most fundamental contribution has been to bring the same mathematical rigor to design decision-making that has long been employed in traditional design analysis, particularly in the areas of preference modeling, design evaluation and trade-offs under uncertainty.

The engineering design community is now keenly aware that decision-making is integral to the design process, rather than an afterthought relegated to others. It is an important element in nearly all phases of design, from defining the problem, synthesizing alternatives, evaluating what is acceptable and what is not, identifying which design elements to work on first, specifying what information is needed and by whom, selecting which alternatives are worth pursuing further and finally configuring the optimal design.

Later chapters in this book will reveal the liveliness of ongoing debates about the pros and cons of alternative DBD approaches. While these debates can be quite interesting, don't let them detract from the central message of this book. In truth, the single greatest contribution of DBD has been to help designers recognize that decision-making has always been integral to the design process; only now we think much more carefully about how to make decisions.