Design Methods

What follows is an abstract from some of the information from a great book by John Chris Jones, called Design Methods (Van Nostrad Reinhold, 1992).

The need for new methods

Jones identifies a number of reasons for the failure of traditional design methods to cope with modern complex design issues. He suggests four critical questions to unearth strengths and weaknesses of traditional methods:

  1. How do traditional designers cope with complexity?
  2. In what ways are modern design problems more complicated than traditional ones?
  3. What are the interpersonal obstacles to solving modern design problems?
  4. Why are the new kinds of complexity outside the scope of the traditional design process?

The final conclusion is this: The search space in which we have to look for feasible new systems, composed of radically new products and components, is too big for rational search and too unfamiliar to be penetrated and simplified by the judgements of those whose education and experience has been limited to the existing design and planning professions. Clearly we need multi-profesional designers and planners whose intuitive leaps are informed by knowledge and experience of change at all levels from community action to component design. Equally we will need new methods that provide sufficient perceptual span at each of these levels.

How do traditional designers cope with complexity?

Jones addresses two types of complexity. The internal complexibility concerns the compatibility of the components of the product itself. An excellent example of a tool here is the scale drawing, which is much used in engineering. A scale drawing, both during its construction and as a final product, enables a designer to concentrate only on certain parts of a design, leaving all other options unchanged. The net effect of this is that at any one time the designer only looks at a small number of design alternatives, because all the other degrees of freedom in the design are constrained.

External compatability is mainly achieved through experience and imagination. The scale drawing can't help to predict how the product will fit into its environment. Experience and imagination are fairly vague, but research so far is not conclusive. Three common items always seem to surface:

  1. Often the designers doesn't seem to make any progress, or only trivially, just taking in information. This is known as incubation.
  2. Solutions to difficult problems will come suddenly, and take the form of dramatic change. Often this transforms a complicated problem into a simple one.
  3. The enemies of originality are mental rigidity (keeping with familiar grounds) and wishful thinking (ignoring external realities).

This comes down to a transformation from something complicated to something simple. Such a transformation depends on two things:

Summary: In traditional design methods, the complexities of designing are dealt with by using a tentative solution as a rapid means of exploring both the situation that the design is to fit and the relationships between components of the design.

In what ways are modern design problems more complicated than traditional ones?

Jones makes an interesting claim for better design methods by pointing at the many unsolved problems created by the use of man-made things. He claims they can be thought of as human failures to design for conditions brought about by the products of designing.

Jones claims that design should not concern itself solely with the components and products levels, but also with the systems and community levels. While this larger scope allows for much more attention to the consequences of design, it also greatly reduces stability, and enhances complexity. This instability is a permanent condition. "To design is no longer to increase the stability of the man-made world: it is to alter, for good or ill, things that determine the course of its development."

The last statement implies that we should not trust what was possible in the recent past, but rather venture into what will be possible in the future.

Jones finally lists a number of complexities which have risen:

What are the interpersonal obstacles to solving modern design problems?

Jones wonders about Designing by Committee. He states that this can easily fail if the committee is not up to the task, but also claims that a good committee will work very well, if all commmittee members are aware of each other, and have a common goal.

He also lists the different organizations through which a design will pass, and notes possible difficulties can arise when design takes place at both the system and the product level.

The sponsors often give only a limited brief to the designers. The designers may in turn come up with a wider revised brief which they find needed to achieve a gross rather than a marginal improvement. The sponsors may not be able to like or accept this new vision for their own future.
Design Team
Often new team members will be added to a design team in order to account for shifting boundaries within the project. This gives rise to a number of problems: team members don't know enough about each other; they may be tied to much to current systems or practice; existing components will operate under changed conditions, and hence should be retested.
Suppliers may underestimate their abilities to meet demands for a radically new design. However, they do not have a vested interest in the current product, so they may provide a valuable stimulus.
The producers (i.e. production engineers) have problems estimating the cost of proposed design changes before detailed manufacturing specifications have been worked out. Commen reactions are "impossibly expensive" and "no problem at all".
Briefly put the influence of distributors on proposals for radical improvements depends upon the degree to which customers have begun to ask for it.
Not always the same as the users! Purchasers often base their decision on their ability to predict how they can use the product.

Why are the new kinds of complexity beyond the scope of the traditional design process?

Traditionally coping with complexity is done by working on one sub-problem at the time. This strategy relies heavily on the fact that the designer is able to come up with a promising set of sub-components. This seems to be quite hard to do at the systems level. In summary, several reasons can be identified:

  1. Without something equivalent to a drawing the designer can not concentrate of one sub-problem at a time. A medium to communicate the essence of the design is lacking. Sticking to drawing is no solution either, as it inhibits too many innovations.
  2. No systems are available to allow rapid judgement of the feasibility of critical details. This makes it hard to transform a complicated problem into a simple one. The information needed to assess this feasability is scattered beyond recognition.
  3. Many of the people who have information upon which the new design depends will make biased judgements because of their vested interests.

Design Methods

Jones also describes a number of design methods which address some of the points mentioned above. He uses the following items to describe a design method:

The title of the method. Should make clear what the method is about.
Describes what the results of this method are in a single sentence.
Brief description of the steps and action involved in this design method.
Several examples showing the design method in action.
Brief assessment of the effectiveness and usability of the method, including application in practice.
Kinds of situation in which this method can be used.
How easy is it to learn and use this method.
Time and cost
How much time is needed to carry out this method, and what are the associated costs.
References to e.g. original publications, and other relevant publications.