InnovationDesign

Design Thinking Explained — Method, Phases, and the Best Tools

Alexander Sattler 20. March 2026 4 min read

Design Thinking is more than sticky notes and colorful rooms. It is a systematic approach to solving complex problems from the user's perspective — developed at Stanford's d.school and popularized by IDEO and the Hasso Plattner Institutes. The core principle: before you build a solution, you need to truly understand the problem. Sounds obvious, but it's surprisingly rare in practice. In this article, we explain the method, its phases, and the tools that deliver the most value at each stage.

DEFINITION

Design Thinking is a human-centered innovation approach that works in iterative cycles. It combines empathy for the user, creative ideation, and rapid prototyping to develop solutions that are technically feasible, economically viable, and desirable for people.

1
Framework

Double Diamond

The Double Diamond is the process model that most clearly visualizes the Design Thinking workflow. Developed by the British Design Council, it shows four phases in two diamond shapes: Discover (divergent: explore the problem space), Define (convergent: narrow down the problem), Develop (divergent: generate solutions), Deliver (convergent: implement the solution). The model makes visible what many teams get wrong: they jump directly from a vague problem to the first solution — without truly exploring the problem space. The Double Diamond forces you to think divergently first (open up options) before converging (making decisions). This pattern repeats twice: once for the problem, once for the solution.

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2
Canvas

Design Thinking Canvas

The Design Thinking Canvas brings the entire process onto a single page and works excellently as an overview for teams experiencing Design Thinking for the first time. It visualizes the five classic phases — Empathize, Define, Ideate, Prototype, Test — as a connected worksheet. Each phase has space for insights, hypotheses, and next steps. The advantage over a blank whiteboard: the canvas provides structure without constraining creativity. It prevents teams from getting stuck in the ideation phase and never reaching prototyping.

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3
Canvas

Empathy Map

The Empathy Map is the most important tool in the first phase (Empathize). Developed by Dave Gray, it captures what the user says, thinks, does, and feels across four quadrants. The insight: between what people say and what they actually do, there is often a huge gap — and that's exactly where the most interesting findings lie. In practice, we fill out the Empathy Map after user interviews or observations, not before. An Empathy Map based on assumptions rather than real data is dangerous because it creates false confidence.

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PRO TIP

Pro tip: Always fill out the Empathy Map as a team, never alone. Everyone hears different things in an interview. The discussion about contradictions between 'says' and 'does' is often more valuable than the map itself. Schedule at least 30 minutes for this after each interview.

4
Canvas

Persona Canvas

The Persona Canvas goes a step further than the Empathy Map and condenses user insights into a fictional but data-based archetype. A good Persona Canvas contains demographic data, goals, frustrations, preferred channels, and a quote that captures the person's attitude. Important: personas only work when based on real interviews. A persona invented at a desk merely confirms existing assumptions. We recommend at least 5-8 interviews per persona to identify reliable patterns.

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5
Guide

Design Thinking Bootleg

The Design Thinking Bootleg from Stanford's d.school is the most comprehensive freely available method collection for Design Thinking. It contains dozens of methods for every phase — from interview techniques to brainstorming variations to prototyping methods. The Bootleg is not a textbook but a toolbox: each method is described on a card with step-by-step instructions. For facilitators it is indispensable because it offers the right format for any workshop situation.

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CAUTION

The biggest mistake in Design Thinking: jumping to solutions too early. Teams skip the Empathize and Define phases because they're impatient or believe they already know the problem. In reality, the problem statement changes fundamentally after the first user interviews in 80% of cases. Invest at least one-third of your total time in understanding the problem.

PhaseGoalBest toolTypical mistake
EmpathizeTruly understand usersEmpathy MapUsing assumptions instead of interviews
DefineFormulate the problem preciselyDesign Thinking CanvasToo vague or too broad problem statement
IdeateGenerate many solution ideasDesign Thinking BootlegImplementing the first idea immediately
PrototypeMake ideas tangibleStoryboard TemplateBuilding too detailed, too perfect
TestGet feedback from real usersPersona CanvasAsking only colleagues instead of real users
The 5 phases with matching tools

KEY TAKEAWAY

Design Thinking is not a linear process. It's a loop: every test can take you back to the Empathize phase. Accept that — it's not failure, it's the system working as intended.

CONCLUSION

Design Thinking unfolds its power when you take the phases seriously and don't cut corners. Start with the Double Diamond as your process model, use the Empathy Map and Persona Canvas for genuine user understanding, and turn to the Design Thinking Bootleg when you need specific methods for your workshop. The Design Thinking Canvas ties everything together. The most important advice: spend more time with the problem than with the solution.

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