TL;DR: Design methods are often based on in ideas that were popular in the early 20th century: scientific positivism and industrial production. This hides essential, but messy aspects of design.

In his book The Reflective Practitioner, Donald Schön uses a concept named “Technical Rationality”. It is the idea, that there are clear problems, clear solutions and processes which provide the path from problem to solution, all based on science. Practitioners apply these processes that are given to them by science; then they build what the process suggests as a solution. Because of this, practitioners have a lower status, since all the intellectual work is done in the science-part of the concept.

In The reflective Practitioner ¹ Schön connects this to the idea of positivism: Scientific positivism–very simplified–assumes that only empirical data and logic should be used to generate valid knowledge; findings can be verified; the social behaves according to universal laws (similar to physics).

Another idea can also be connected to the approach of technical rationality: Industrial production. This is less present in the reflective Practitioner, but in his book Technology and Change ². The idea of industrial production is that processes can be split into clear steps, just like products are assembled step wise in a production line. Each steps can be optimized on its own and takes the previous’ step’s output to convert it to input for the next step ³.

Technical Rationality in the design process

The foundations of technical rationality, scientific positivism and industrial production are not very popular. Scientific positivism is philosophically really dead ⁵. The industrial production on assembly line is widely used, but our future is said to be the knowledge economy, self-organized teams and agile processes.

Nevertheless, technical rationality is alive—also in design. This is reflected in the rhetoric we talk in order to teach, explain and justify design:

Claims of Foundations in natural sciences producing truth

We talk about findings being verified and product ideas being validated, like findings in positivism. The job title of a user researcher conjures the image of natural or at least empirical science.

Processes are presented as orderly, step-wise and based on the idea of input/output in each step

Design processes are often represented in a linear and step-wise way ⁴. That matches the idea of the design process as a production line, with clearly marked steps that feed each other input. Even though some processes highlight the possibilities of iteration, there is still an assumed usual order of steps.

Believe in the existence of a right problem that should be tackled

The “right problem” is the start of the process in technical rationality. It is the very first step before you apply (empirical) methods to solve your problem, so it needs to be somehow bootstrapped. This first step is highlighted as essential in popular design methods:

“Before the sprint begins, you’ll need to have the right challenge”

– (Google Ventures Design Sprint, 30.5.17)

“Properly framing your design challenge is critical to your success. Here’s how to do it just right.”

–(IDEO.org’s Design Kit on “Frame Your Design Challenge”, 30.5.17)

The technical rationality view of design processes clashes with philosophical and empirical views on design

These basic assumptions of scientific foundations, step-wise processes and root problems conflict in several ways with design philosophy and design research:

Design as scientific process

Design is not the same as science: Nigel Cross described “Designerly Ways of Knowing” : While natural sciences are concerned with the natural world and values like “objectivity, rationality, neutrality, and a concern for ‘truth’” ⁸, design is concerned with the “man-made world” and values as “practicality, ingenuity, empathy, and a concern for ‘appropriateness’” ⁸.

This is matched by empirical research of design processes: Rogers described methodological frameworks and contrasted them with practitioners’ opinions. Theories were not practical for most designers ¹². Other studies on method use by designers yielded similar results, e.g. ^{11 16}. The complexity in the design process can not be adequately handled by current scientific theories ¹⁰.

Design as a non-linear process

Rationality of Design work is shown by having a process. But designers seem not to use a process that is divided into clear steps. For example, no hierarchical problem decomposition takes place, even if the designer claims it does ^{14 15}.

According to methods like design thinking (or at least according to simplistic implementations of it), requirements should be defined before building a prototype, but it seems that designers discover and add requirements in the process of creating solutions ¹⁷. The modes like problem analysis or prototyping are switched if it is cognitively more economic to use another mode ^{14 15}–and this is not always when a method suggests it.

Design Research on “Right goals”: Solution and problem are both changed over time

Design is a way to solve entangled, “wicked” problems that have unclear conflicting constraints, multiple stakeholders with different needs, and in which creating a solution also changes the context ⁶. A design problem’s wickedness conflicts with the basic premise of having the “right problem” at the start of the process. The assumption of a single root cause (like in the popular 5-Why method) can lead to simplistic views ¹⁹.

The assumption that finding the “right goal” is essential is also not supported by design studies ²⁰. “It appears that successful design behavior is based not on extensive problem analysis” ⁷ One reason for this might be that there are no inherent “right goals” in design—on the contrary: The assumed problem and its proposed solution are intertwined ⁹. This means, that when the solution is developed also another understanding of the problem is developed. This reframing—a problematic behavior when viewed from the assumption of “right problems” seems to be essential for high quality design solutions ¹³: To stick with one right problem can actually hurt in finding a right solution.

Conclusion

Many design methods are based on the assumptions of technical rationality and use positivist ideas of research and verification as well as production line models with stepwise creation of a solution. These ideas conflict with views based scientific and philosophical studies of design:

• Design can not use the same principles as science
• The wickedness of many interesting problems defies essential assumptions of clarity of problem and solution.
• There does not seem to be a strict order of steps and the methods applied in them (but an opportunism of the use of whatever seems to work best)

In practice, the clash between technical-rational assumptions and practice²¹ may hinder good outcomes e.g. by keeping people from rewriting their goals and discouraging jumping between methods. They may also obscure the strengths of design: It’s applicability to wicked problems, where no root causes can be found.

We should be aware that popular design methodologies often come with their own assumptions, assumptions which often embody 20th century ideas of industrial production and science.

Changes

• Updated at 2017-09-27: Reference to Gedenryd’s How Designers Work.
• Updated at 2017-12-19: Footnote on relation to The politics of formal representations (S.L Star) added.
• Updated at 2018-06-23: Link linear process representation to Gedenryd’s How Designers Work.
• Updated at 2018-07-05: Add note on Herbert Simon’s influence on rational models of design.
• Updated at 2018-07-08: Note on “thick desciption”, Geertz
• Updated at 2018-09-23: Note on communication
• Updated at 2019-02-01: Notes addition of Nature Normative (2008) and Formalized System Development Methodologies (1996)
• Updated at 2019-11-14: Notes on Ingold and an idea on prescribed design processes being plans for the creation of plans.
• Updated at 2021-01-02: Note on Buckminster Fuller
• Updated at 2021-07-24: Second note on Nature Normative (2008); some small changes (changing the year of the previous note to 2021, not 2020 and some formatting)
• Updated at 2024-01-30: Added note on Umstrittene Methoden
• Updated at 2024-03-12: Added note on Against Method

Notes:

• An interesting related topic I discovered after writing this is the issue of representing outcomes of user research. Wilkie describles in User assemblages in design how an imagined-user-representation (“Persona”), is created in a messy process, that is then presented as clean and rational (For such retrospective “clarity”, Weick’s Sensemaking in Organizations might be an interesting related resource) ; Nafus and Anderson discuss the use of naturalist presentation of applied ethnographic research (“real users”, “actual behavior”) ²³ . This is related to the above topics of producing truth and existence of right problems.
• Herbert Simon's ideas played a large role in seeing the design process as rational. Gedenryd ⁴ is referring mainly to his work with Newell, Human Problem Solving, while Brooks ²⁴ focuses Simon’s "The Sciences of the Artificial". Donald Schön also refers to Simons ideas in "The Sciences of the Artificial", highlighting that Simons idea of design depends on “having well-formed instrumental problems to begin with”
• In “Thick Description”, Geertz describes the problems of appying a phases model to ethnographical work: “…“He observes, he records, he analyzes”—a kind of veni, vidi, vici conception of the matter—it may have more deep-going consequences than are at first apparent, not the least of which is that distinguishing these three phases of knowledge-seeking may not, as a matter of fact, normally be possible; and, indeed, as autonomous “operations” they may not in fact exist.” (p.22)²⁵
• While I still think that the technical-rational assumptions are problematic, many seem to create opportunities for communication and ways of coordination. E.g. Assuming you have to find the “right” problem allows to discuss the problem; being in the “evaluation step” allows to focus people on a specific set of tasks.
• An interesting overview of formalized methods in development is: Fitzgerald, Brian. 1996. “Formalized Systems Development Methodologies: A Critical Perspective.” Information Systems Journal 6 (1): 3–23. https://doi.org/10.1046/j.1365-2575.1996.00100.x.
  “An examination of the literature reveals a two-fold bias, which, firstly, construes the `software crisis' as a problem arising from the sloppy, ad hoc and irrational approaches of systems developers in practice; and, secondly, views the solution to the software crisis in terms of more widespread adoption of rigorous and formalized systems development methodologies.”
• The relation of design methods to cybernetics is very interesting. Cybernetics emphasizes exchange of information and feedback and thus has some connections to the mathematicalized models of Simon (see above). See: Upitis, Alise. 2008. “Nature Normative: The Design Methods Movement, 1944-1967.” Massachusetts Institute of Technology.
• Ingolds writes about the split of skilled making into design and execution: “The thing, we say, is virtually ‘conceived’ in advance of its realization in practice.”²⁶, an idea he also links to modern biology and genetics ²⁷. However, whereas Ingold talks about the split between creating-a-plan for things and making things, a prescribed design process does the same on a meta level: It makes a plan of how to create a plan to create a thing.
• I already mentioned the connection to cybernetics above. Whereas Simon comes from AI, you also have people like Buckminster Fuller, which are closer to what people commonly understand as designer. His ideas are also quite close to design imagined as an overarching, coordinating, patter-revealing discipline that exists outside of other disciplines and unites them: “The comprehensive Designer would not be another specialist, but would instead stand outside the halls of industry and science, processing the information they produced, observing the technologies they developed, and translating both into tools for human happiness. … He would then act as a “harvester of the potentials of the realm,” gathering up the products and techniques of industry and redistributing them in accord with the systemic patterns that only he and other comprehensivists could perceive.” Turner, From Counterculture to Cyberculture, 2006 ²⁸. Fuller’s ideas influenced Steward Brand, whom Turner describes as a key figure in shaping silicon valley culture.
• In “Builders of the Vision: Software and the Imagination of Design”, I came across the “Albertian ideal of building” which is “…the execution of designs by an infinitely precise skilled craftsman … and it has not yet lost its hold upon our collective imagination of design. The reason is clear enough. Aligned with a long-standing Western tradition of privileging mind over matter, the Albertian split detached the mental sphere of design from the physical sphere of materials, installing the authority of the architect over artisans and builders.” Albertinian refers to Leon Battista Alberti.
• A historical perspective on the conflicts discussed here can be found in Fezer’s “Umstrittene Methoden” ²⁹: Design methods are closely related to rationalization of design and thus the ability to give a justification of why decisions were taken. This allowed to dicsuss decisions and thus a politicization of design. This meant that the role of design and designers needed to be negociated around the question of who designers do serve and who decides on what should be done. The question of how to research without massive budgets and without assuming an a normative avarage led to direct participation; Goals needed to be negociated since values came to be seen as crucial; top-down design was replaced by open processes and self-direction; The movement, however split up, some went into more pure academic fields like sociology while architecture moved towards postmodern styles.
• Schön’s critique of professional work trying to model itself on scientific research and the assumption that there is first a clear problem, then a solution that is developed, is similar to Paul Feyerabend’s critique of the idea of scientific research in chapter 1 of “Against Method” (im my 1980 verso Paperback its page 26): “Creation of a thing and creation plus full understanding of a correct idea of the thing, are very often parts of the same indivisible process…”