Design as a process

Substantial disagreement exists concerning how designers in many fields, whether amateur or professional, alone or in teams, produce designs. Dorst and Dijkhuis argued that “there are many ways of describing design processes” and discussed “two basic and fundamentally different ways”,^[7] both of which have several names. The prevailing view has been called “The Rational Model”,^[8] “Technical Problem Solving”^[9] and “The Reason-Centric Perspective”.^[10] The alternative view has been called “Reflection-in-Action”,^[9] “co-evolution” ^[11] and “The Action-Centric Perspective”.^[10]

[edit] The Rational Model

The Rational Model was independently developed by Simon ^[12] and Pahl and Beitz.^[13] It posits that:

1. designers attempt to optimize a design candidate for known constraints and objectives,
2. the design process is plan-driven,
3. the design process is understood in terms of a discrete sequence of stages.

The Rational Model is based on a rationalist philosophy ^[14] and underlies the Waterfall Model,^[15] Systems Development Life Cycle ^[16] and much of the engineering design literature.^[17]

[edit] Example sequence of stages

Typical stages consistent with The Rational Model include the following.

• Pre-production design
  • Design brief or Parti – an early (often the beginning) statement of design goals
  • Analysis – analysis of current design goals
  • Research – investigating similar design solutions in the field or related topics
  • Specification – specifying requirements of a design solution for a product (product design specification^[18]) or service.
  • Problem solving – conceptualizing and documenting design solutions
  • Presentation – presenting design solutions
• Design during production
  • Development – continuation and improvement of a designed solution
  • Testing – in situ testing a designed solution
• Post-production design feedback for future designs
  • Implementation – introducing the designed solution into the environment
  • Evaluation and conclusion – summary of process and results, including constructive criticism and suggestions for future improvements
• Redesign – any or all stages in the design process repeated (with corrections made) at any time before, during, or after production.

Each stage has many associated best practices.^[19]

[edit] Criticism of The Rational Model

The Rational Model has been widely criticized on two primary grounds

1. Designers do not work this way – extensive empirical evidence has demonstrated that designers do not act as the rational model suggests.^[20]
2. Unrealistic assumptions – goals are often unknown when a design project begins, and the requirements and constraints continue to change.^[21]

[edit] The Action-Centric Model

The Action-Centric Perspective is a label given to a collection of interrelated concepts, which are antithetical to The Rational Model.^[10] It posits that:

1. designers use creativity and emotion to generate design candidates,
2. the design process is improvised,
3. no universal sequence of stages is apparent – analysis, design and implementation are contemporary and inextricably linked ^[10]

The Action-Centric Perspective is a based on an empiricist philosophy and broadly consistent with the Agile approach ^[22] and amethodical development.^[23] Substantial empirical evidence supports the veracity of this perspective in describing the actions of real designers.^[20]

[edit] Descriptions of design activities

At least two views of design activity are consistent with the Action-Centric Perspective. Both involve three basic activities.
In the Reflection-in-Action paradigm, designers alternate between “framing,” “making moves,” and “evaluate moves”. “Framing” refers to conceptualizing the problem, i.e., defining goals and objectives. A “move” is a (tentative) design decision.^[9]
In the Sensemaking-Coevolution-Implementation Framework, designers alternate between its three titular activities. Sensemaking includes both framing and evaluating moves. Implementation is the process of constructing the design object. Coevolution is “the process where the design agent simultaneously refines its mental picture of the design object based on its mental picture of the context, and vice versa”.^[24]

[edit] Criticism of the Action-Centric Perspective

As this perspective is relatively new, it has not yet encountered much criticism. One possible criticism is that it is less intuitive than The Rational Model.