The Double Diamond

The Double Diamond is a visual model for how design thinking unfolds across two related challenges: understanding the problem, then shaping a solution. Each diamond has a divergent phase (opening up options) and a convergent phase (narrowing to a decision). The Design Council popularised the model to help teams avoid rushing to answers before they have properly explored the question.

Discover and Define — the first diamond

Discover is divergent: gather evidence from users, data, and context. Talk to people, observe behaviour, map the current landscape. The aim is breadth — to surface needs and constraints you did not know about at the start.

Define is convergent: synthesise what you learned into a clear problem statement or opportunity. You are not choosing a solution yet; you are agreeing what problem is worth solving and for whom.

Develop and Deliver — the second diamond

Develop is divergent again: explore possible solutions — sketches, prototypes, alternative flows. Multiple ideas compete until evidence shows which directions are worth pursuing.

Deliver is convergent: refine the chosen approach, build it with quality, test it with users, and launch something that works in the real world. Delivery is not the end — live services continue to iterate.

Why the double shape matters

A single diamond would suggest one cycle is enough. The double shape encodes a crucial discipline: fully explore and define the problem before you commit significant effort to solutions. Teams that collapse Discover and Develop into one messy phase often defend solutions that solve the wrong problem.

The model is not a strict timetable. Within a two-week sprint you might mini-cycle through diverge and converge. Across a multi-month programme, the diamonds describe the dominant mode of work at each stage.

Using it in practice

Name the mode you are in. If the team is generating options, protect time for exploration. If you are converging, make the decision criteria explicit. The Double Diamond is most useful as a shared vocabulary — so researchers, designers, engineers, and policy colleagues know whether the team is still learning or ready to commit.

See how the Double Diamond maps to GDS delivery phasesfor an interpretive view of how this thinking model sits alongside Discovery, Alpha, Beta, and Live.