An appropriate use of the 'solution-focused' approach to design is something that seems to develop with experience. Experienced designers are able to draw on their knowledge of previous exemplars in their field of design, and they also seem to have learned the value of rapid problem-exploration through solutionconjecture. In comparison, novice designers can often become bogged down in attempts to understand the problem before they start generating solutions. For them, gathering data about the
problem is sometimes just a substitute activity for actually doing any design work.
However, novice designers are also frequently found to become fixated on particular solution concepts. Early solution concepts are often found to be less than satisfactory, as problem exploration continues. Novice designers (and sometimes more experienced ones) can be loath to discard the concept and return to a search for a better alternative. Instead, they try laboriously to design-out the imperfections in the concept, producing slight improvements until something workable but perhaps far from ideal is attained. Sometimes it can be much more productive to start afresh with a new design concept.
Another difference between novices and experts is that novices will often pursue a depth-first approach to a problem: sequentially identifying and exploring sub-solutions in depth, and amassing a number of partial sub-solutions that then somehow have to be amalgamated and reconciled, in a bottom-up process. Experts
usually pursue predominantly breadth-first and top-down strategies, as recorded in the example of the expert designer's decision tree in Figure 6 (Chapter 1). Experienced designers, like any skilled professionals, can make designing seem easy and intuitive. Because skilled design in practice therefore often appears to proceed in a rather ad hoc and unsystematic way, some people claim that learning a systematic process does not actually help student designers. However, a study by Radcliffe and Lee (1989) did show that a systematic
approach can be helpful to students. They found that the use of more efficient design processes (following closer to an ideal sequence) correlated positively with both the quantity and the quality of the students' design results. Other studies have tended to confirm this.
From studies of a number of engineering designers, of varying degrees of experience and with varying exposures to education in systematic design processes, Fricke (1996) found that designers following a 'flexible-methodical procedure' tended to produce good solutions. These designers worked reasonably efficiently and followed a fairly logical procedure, whether or not they had been educated in a systematic approach. In comparison, designers either with a too-rigid adherence to a systematic procedure (behaving 'unreasonably' methodically), or with very unsystematic approaches, produced mediocre or poor design solutions.
Successful designers (ones producing better quality solutions) tended to be those who:
• clarified requirements, by asking sets of related questions which focused on the problem structure
• actively searched for information, and critically checked given requirements
• summarised information on the problem formulation into requirements and partially prioritised them
• did not suppress first solution ideas; they held on to them, but returned to clarifying the problem rather than pursuing initial solution concepts in depth
• detached themselves during conceptual design stages from fixation on early solution concepts
• produced variants but limited the production and kept an overview by periodically assessing and evaluating in order to reduce the number of possible variants.
The key to successful design therefore seems to be the effective management of the dual exploration of both the 'problem space' and the 'solution space'.
Designing is a form of skilled behaviour. Learning any skill usually relies on controlled practice and the development of techniques. The performance of a skilled practitioner appears to flow seamlessly, adapting the performance to the circumstances without faltering. However, learning is not the same as performing,
and underneath skilled performance lies mastery of technique and procedure.
Engineering Design Methods
Strategies for Product Design
THIRD EDITION
Nigel Cross
The Open University, Mi/ton Keynes, UK
JOHN WILEY & SONS, LTD
Chichester- New York. Weinheim • Brisbane. Singapore. Toronto
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