Andreas Soller

What is Design Thinking?

Brief overview of Design Thinking and of the Double Diamond model as the most common process model applied with Design Thinking.


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10 min read (2295 words)

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May 9, 2022 – Updated Dec 17, 2023, 10:33

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Why Design Thinking?

Usually innovative new ideas don't come out of the blue but are already part of something. The process of value creation usually does not depend on one ingenius inventor but on a structured way to fully understand a given situation and — as an example — what problems (or benefits) could be solved (brought) to specific user groups in this situation. Often, this does not even involve pure novelty but rather a reorganization / recombination of something already existing. This means we collect real world data to put ourselves in the shoes of people who are in this situation (human-centered approach) in order to understand what creates value for those users.

Design Thinking not only guides us to understand and come up with ideas how to solve those problems (and therefore, truly understand the benefit solutions might bring) but also help us also to circumvent artificial impediments. Often, large companies have created their own immune system such as a certain company culture how a project must be run/owned or legacy IT infrastructure that determines how solutions can be build. With Design Thinking we do not immediately kill ideas that don't fit a certain company context but rather ask what if this idea would be brought to life? What if anything were possible?

Thinking out of the box will help us to first focus on value creation, on understanding the full potential of ideas before we dismiss them. An idea does not live in an ivory tower but is rather a business concept that is based on certain facts and solution assumptions. We call those ideas hypotheses.

The next step is to find out what hypotheses might bring the highest value. To do so we test the most promising hypotheses with people we expect to need those solutions. To do so, we use prototypes. This validation is also called an experiment – we want to learn in the real world if an idea is worth to be continued, needs amendments or should be dismissed. Of course, testing also involves the company structure and impediments if a certain hypothesis is feasible or not and – looking at profit oriented organizations – if a product / market fit can be established.

This process is fast and iterative: Real-world feedback cycles help us to learn fast, adjust our assumptions and improve our hypothesis based on facts. This is called a user-driven approach that helps us to constantly shape our solutions based on the values it should bring for its users, other stakeholders and the organization providing those solutions.


Design Thinking is not a one-time-activity but rather a methodolgy and a mindset how to approach the process of idea creation, validation and constant adoption.

What is Design Thinking?

Design Thinking = to design thinking.

The process of thinking itself is shaped: we shape the way how we understand and solve problems by focusing on the needs and motivations of people for whom this problem exists. The process itself is collaborative: problem-solving is most effective when people from different disciplines work together in an environment that supports creativity.

Core practices of Design Thinking

Jeanne Liedtka has defined the following five core practices of Design Thinking:

  1. Develop a deep, empathetic understanding of the needs and context of those for whom (and with whom) we are designing
  2. Form diverse teams
  3. Create multiple solutions (hypotheses) and make them tangible and testable
  4. Foster conversations that encourage dialogue instead of debate
  5. Offer a structured and facilitated process

(Liedtka 2021:13)

Design process models

For a better understanding how Design Thinking works, it helps to apply it to a design process model.

There are many models and we will first focus on the Double Diamond model that became popular in 2011 when promoted by the British Design Council. (This model was extended in 2021 and you can find a link to the revised version in the reference section of this article.)

The Google Design Sprint builds on top of the double diamond model and tries to incorporate the whole process within one week. A lot of companies run Design Thinking Workshops which are in essence very condensed variations.

Another process model that grew directly out of Design Thinking is for instance the four question approach – What is? What if? What wows? What works? – by Jeanne Liedtka.

Those process models gives an idea how to collaboratively and iteratively solve problems with a human-centered approach. A process model complements Design Thinking by providing a structured framework. We will look at the Double Diamond model and the four questions approach to give a more comprehensive overview of what Design Thinking aims at.

If you are interested in design models in general I recommend the Book “How do you design?” by Hugh Dubberly. See reference section for a link to this book.

Double Diamond

In 1996 Béla H. Bánáthy proposed the divergence-convergence model in his book “Designing Social Systems in a Changing World”. This design process model became popular when it was enhanced and published by the British Design Council as Double Diamond model in 2005.

  • Divergent thinking refers to exploring and building up a deeper understanding: create options.
  • Convergent thinking refers to having fully understood the options and hence, to be able to make a choice.


Discover refers to all activities to get a deep understanding of the problem.

In this first phase you might together

  • observe and
  • talk to users,
  • execute desk research to understand how this problems are approached in other contexts,
  • you will run surveys and
  • check quantitative data,
  • map different context situations over time,
  • etc.

As of research triangulation is key: that means you will combine different research methods such as interviews, observations and quantitative data to get a fuller picture.


In this phase, the team will get a deep and shared understanding of the problem space.


Define refers to all activities to come up with a first problem statement.

You will analyse your findings together

  • and create personas to get a better understanding of user segmentations,
  • use frameworks such as jobs-to-be-done to understand the tasks
  • use mapping techniques such as User / Customer Journey Mapping for the different user groups (personas),
  • create a service blueprint in case you want to analyse the User Journey together with internal processes,
  • etc.

The goal is that you come up with a single problem statement:

GIVEN THAT (context, situation)
HOW MIGHT WE (question)
SO THAT (goal, objective)
BECAUSE (need)

A good problem statement is

  • specific enough to address the problem it wants to tackle,
  • broad enough that it doesn't specify the solution upfront,
  • has a multifunctional perspective and
  • inspiring to the participants that they want to solve it.


In this phase, the team will come up with a single problem statement as starting point to explore possible solutions.


Design refers to exploring potential solutions.

In this phase you will ideate together and

  • phrase refined hypotheses,
  • create storyboards and
  • rapid prototypes
  • to validate your ideas.

Rapid prototyping refers to shitty first drafts that you can you to extend your learning about possible solutions. You don't create high fidelity prototypes but rather quick prototypes to get fast feedback. A rapid paper prototype will also give you more insights as long as you are exploring, as first test users will more easily tell you what is still missing or what can be changed.

Don't focus on specific ideas but rather go for different ideas. Think holistic and run rather full service concept pilots instead of very specific solution assumptions.


In this phase the team will have further enlarged their problem understanding by exploring various ideation techniques. Additionally, the team has iterated and validated various ideas and build up knowledge about the impact of various solution assumptions.


Deliver refers to all activities where you evaluate different solution assumptions.

You will together

  • define criteria
  • to select options,
  • check impact objectives
  • do final validations,
  • come up with action plans,
  • and a concrete solution assumption
  • etc.


In the last phase the team will have come up with a concrete solution assumption – the next best test (MVP).


Most important, Design Thinking is not a one-way-street but rather an iterative process where continuous touch points with the users are key. It is not enough just to create some output. Instead you focus on outcomes for the users that will use your product or service. The process requires a constant reality check and continuous learning.

You just deliver the smallest output that is needed to test your assumption with a large enough sample to gather enough confidence for next steps. With new learnings you will either move on or iterate each of the four phases.

It can also happen that the outcome of one loop is a readjustment of the initial problem assumption. In this situation you iterate the full loop once more.

What is? What if? What wows? What works?

Whereas the Double Diamond model is suitable for any human centered problem solving context, the four questions approach puts business growth at its center.

Thinking about innovation and growth, Jeanne Liedtka and Tim Ogilvie proposed the four questions and then methods approach in their book Designing for Growth. In the following paragraphs I will outline the main concept and the proposed methods except one – visualization – as visualization is at the heart of everything. In Design Thinking you don't just talk about concepts but rather make them as tangible and concrete as possible. Therefore, visualization is at the core of the whole process. Be it as a rough sketch, prototype or just the grouping of some post-its. We always try to structure and organize information in a visual way.

The Business Model Canvas is for example another tool that can be used in either of those approaches and I use this to hightlight that Design Thinking is a very flexible and dynamic approach. The core principles highlighted earlier at this article are what binds Design Thinking together. It is up to the concrete problem and your organizational context, what techniques you apply.

What is?

In this stage you want to understand and explore the current reality of your users. What problems do your users face with regard to your business?

It is advised to stay open minded and to not focus on specific problems already. The outcome of this stage is a better understanding of problems which you can then turn into opportunities.

Techniques applied at this stage:

  • User Journey Mapping: understand your users journey when they try to get a specific job done
  • Value Chain Analysis: understand your organization's interactions with partners to produce, market, distribute and support your products and services. As an equivalent to the User Journey Mapping you want to understand the opportunities in the whole production value chain. This is particularly useful when exploring growth potential.
  • Mind Mapping to immediately start visualizing your data in order to detect patterns.

What if?

Once you have a better understanding of the user problems, you will phrase hypotheses of how those problems can be solved:

“During the What is stage, we looked at how customers currently frame their problems and the mental models and constraints that we impose on them. Now we'll use this information to formulate hypotheses about new possibilites.” – Liedtka 2011:49

Techniques applied at this stage:

  • Brainstorming to generate as many ideas as possible without evaluation. Brainstorming can help to create something completely new and it is done together to utilize different perspectives on the problems.
  • Concept development starts with choosing the best ideas from brainstorming. It's about making those ideas concrete to evaluate them from a user and business perspective.

What wows?

Now that we have a good understanding of the problem we need to solve and we have created many possibilities, we need to identify and test those assumptions that hit the sweet spot and will lead to a product/market fit.

Techniques applied at this stage:

  • Assumption testing: Any new concept is a hypothesis that needs validation. You treat each concept as a well-informed guess about solving a problem. Therefore, those assumptions are tested in the field (often as rapid prototypes) or confirmed with available data.
  • Rapid prototyping is creating visual representations of those assumptions. This can be simple paper prototypes or rough clickable prototypes. Anything, that helps to validate assumptions with users. Important: a prototype is not a goal in itself. It is just a tool to make our concepts testable.

What works?

In this stage we confront our hypotheses with reality: usually we start with low-fidelity prototypes that we refine based on our learnings before we start implementation.

Techniques applied at this stage:

  • Customer co-creation: Invite potential users and test your prototypes together, observe their reactions and follow-up on the findings with iterations on those prototypes. You start with low fidelity prototypes and once the confidence grows you move towards high fidelity prototypes.
  • Learning launch This is an experiment that is executed in the intended market. There are always some critical assumptions left and a learning launch helps to get a deep understanding how much for your users is at stake. Are they really using it. Why or why not? What learnings can you gather to improve it further before it hits the full market?

References and further reading material:

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