What it actually is, why the evidence supports it, how the Double Diamond works, and what separates genuine design thinking from a room full of sticky notes and good intentions.
Let's be clear first
Design thinking is
Design thinking is not
The Design Council's Double Diamond
First developed by the Design Council in 2005, the Double Diamond has become the world's most widely adopted innovation framework. It maps the design process across two diamonds — each representing a cycle of divergent and convergent thinking. The genius of the model is its insistence that you must do this twice: once to find the right problem, once to find the right solution.
First Diamond · Divergent
⟡ Put people firstThe Discover phase is about going wide and challenging everything your organisation assumes it knows. The instinct is to jump to solutions — design thinking requires you to resist this. You talk to people who live the problem. You watch, observe, and listen. You map who is affected, how, and why. You specifically seek out the people who are always left out of the research. The goal is not confirmation. It is surprise.
Good discovery surfaces things your organisation did not expect. If it confirms everything you already believed, the research was not rigorous enough.
First Diamond · Convergent
⟡ Communicate visuallyThe Define phase is where you synthesise everything you found into the real problem. Not the symptom that shows up in board reports. The root cause worth solving. This is the most underrated stage in design thinking. Most organisations skip it — they research briefly and then generate solutions for the problem they already assumed they had.
A well-defined problem is worth more than a hundred ideas built on a blurry one. The outputs of this stage — affinity maps, POV statements, "How Might We" questions — are not bureaucratic documents. They are shared understanding. When a team can all point to the same sentence and say "that is the problem we are solving," the quality of everything that follows improves dramatically.
Second Diamond · Divergent
⟡ Collaborate & co-createThe second diamond opens with Develop — and the rule is the same as before: go wide. This time, wide on solutions. The worst thing a team can do at this stage is edit before they ideate. Quantity before quality. No judgement during generation. The goal is to have a large enough pool of ideas that choosing the best one becomes possible, rather than defaulting to the most obvious.
The best ideas in Develop sessions rarely come from experts in the problem — they come from borrowed thinking. The GE MRI scanner that stopped making children cry was redesigned by someone who thought about it like a theme park designer, not a medical engineer. That is the discipline of Develop: looking for principles from unexpected places.
Second Diamond · Convergent
⟡ Iterate, iterate, iterateDeliver does not mean launch. It means put something in front of real people and learn. The Design Council's framework is explicit that Deliver is not the end of the process — it is the beginning of a loop. Build the roughest thing that can still test the idea. Paper prototypes have uncovered more valuable insights than polished mockups, because real users tell the truth more readily to rough things that feel changeable.
The discipline of Deliver is iteration. Not "what is the right answer?" but "what did we learn, and what changes as a result?" The teams who move fastest are the ones who test earliest and remain genuinely open to the possibility that their best idea needs significant change before it is worth building.
The evidence
What it looks like in practice
"We don't need a better machine. We need a better experience."
In the early 2000s, GE Healthcare was building world-class MRI machines — technically excellent, clinically effective, deeply frightening to children. The scans required children to lie completely still inside a large, loud, unfamiliar tube. Up to 80% of paediatric patients required sedation to complete the procedure. Parents stood outside distressed. Clinical staff worked to contain fear rather than deliver care.
The engineering team's default was to look at the machine. Make it quieter. Make it faster. Make the hardware less threatening. But a designer named Doug Dietz, working for GE, went to watch what actually happened. He stood in the radiology department and observed a child walking toward the machine. He saw her face change. He saw the moment the fear arrived. He realised: the problem was not the machine. The problem was the entire experience — from the car park to the changing room to the corridor to the room itself.
Dietz borrowed thinking from an unexpected place: the designers who build immersive environments for children's theme parks. He reframed the MRI machine not as medical equipment but as the centrepiece of an adventure story. He designed a series of "MRI adventures" — pirate ships, space missions, underwater journeys — where the machine became part of a narrative the child was living through. Staff were trained as characters in the story. The room, the lighting, the sounds, the instructions were all rewritten.
The result: patient satisfaction scores increased by 90%. The need for paediatric sedation dropped dramatically. The approach cost a fraction of a hardware redesign. It spread to hospitals across the United States.
The problem was never the machine. It was always the experience. Design thinking found the real problem by watching, empathising, and refusing to accept the first framing of the challenge.
Design Council Framework for Innovation
These four principles sit at the heart of the Design Council's Framework for Innovation — the evidence base behind 25+ years of design-led change in public services, healthcare, government, and business. Every stage of Deety is built around them.
Start by developing a deep understanding of the people using a service, the system, or those affected by the problem. This means going beyond surveys and assumption-based personas to genuine observation and conversation. Design thinking insists that the people most affected by a problem are also closest to understanding what a real solution requires. They are not just the subject of the research — they are its most important source.
Use imagery, prototypes, and visual tools to communicate ideas — not just words and reports. Thinking that can be seen can be challenged, refined, and built upon. A visualised insight cluster, a rough prototype, a journey map pinned to a wall — these create shared understanding across a team in a way that a document never can. The goal is not aesthetics. The goal is clarity that enables better decision-making.
The best outcomes in design thinking emerge from diversity — of discipline, perspective, and lived experience. Working together and bringing in people who are not usually part of the conversation consistently produces solutions that experts working alone miss. This is not soft management theory. It is a documented pattern: the GE MRI redesign, the Pentagram NHS identity reform, the IDEO school of management at Stanford — all were co-created with people outside the traditional design team.
Test early, learn continuously, and be willing to change direction. The assumption that the first good idea is the right idea is the most expensive mistake in innovation. Design thinking builds in structured checkpoints where real-world feedback replaces assumption. The organisations that deliver the most through design thinking are not the ones who had the best ideas — they are the ones who remained the most genuinely open to changing them.
Why the method holds
Most organisations invest heavily in solving problems they have not fully understood. Design thinking's insistence on a rigorous Discover and Define phase before generating solutions means the investment in solutions goes toward the actual problem — not its surface symptom. This is where most of the ROI lives: not in better ideas, but in better-defined problems.
The cost of discovering a fundamental flaw in a solution increases exponentially the later it is found. Design thinking deliberately moves testing early — when prototypes are rough, when change is cheap, and when teams are still open to it. IBM's 75% faster shipping rate was not because their teams worked faster. It was because they stopped building the wrong things.
Design thinking is not a one-time intervention. Organisations that embed it consistently develop an institutional capacity for human-centred problem-solving that compounds over time. Teams become faster at empathy research, sharper at synthesis, more disciplined about iteration. The McKinsey Design Index found this capability gap accounts for most of the performance differential between design leaders and the rest.
Enter the Loom — the gamified Double Diamond workshop. Five zones, real challenges, live studio feedback.