UX Glossary · D
Double Diamond
A design process model with four phases: discover, define, develop, deliver, alternating divergent and convergent thinking.
The Double Diamond is a visual model of the design process published by the British Design Council in 2005. Two diamonds sit side by side, each widening then narrowing:
- Discover (diverge): explore the problem broadly
- Define (converge): decide which problem to solve
- Develop (diverge): explore solutions broadly
- Deliver (converge): build and refine one
The point most people miss
The first diamond is about the problem, not the solution. Its output is a problem statement, and the widening is genuine: you are looking for the problem worth solving rather than confirming the one you arrived with.
Most teams skip straight to the second diamond, exploring solutions to a problem nobody examined. The model’s whole contribution is insisting on the first one.
Limits
It reads as linear and design is not. The Design Council’s later framework for innovation added a continuous loop and explicit attention to leadership and engagement, partly to address exactly that reading.
In practice
It is most useful as a communication tool. Explaining to a stakeholder why week one is not producing screens is much easier with the diagram in front of you, and “we are still in the first diamond” is a sentence that lands.