Double diamond

The Double Diamond is a visual model for the design process, developed by the British Design Council. It describes four phases of work - Discover, Define, Develop, Deliver - arranged in two connected diamonds. Each diamond represents first diverging (exploring widely) then converging (focusing on specifics). The framework provides a simple mental model for navigating complex design and product challenges.

Why it matters

Product development requires two different modes of thinking. Sometimes you need to explore broadly - understanding problems, generating options, considering possibilities. Other times you need to narrow down - making decisions, refining solutions, completing work. Teams often struggle because they're in the wrong mode for their situation.

The Double Diamond makes these modes explicit. It shows when to diverge and when to converge, when to ask questions and when to answer them. This clarity helps teams navigate uncertainty purposefully rather than randomly.

For product managers, the Double Diamond provides vocabulary for discussing where you are in a process and what mode of work is appropriate. "We're still in Discover - let's not converge on solutions yet" communicates approach and expectation.

The four phases

Discover (Diverge) - Explore the problem space broadly. Research users, observe behaviors, gather data, and build understanding of the context. Don't narrow prematurely - let insights emerge. The goal is to understand the challenge deeply, not to solve it yet.

Define (Converge) - Synthesize discoveries into a clear problem definition. What specific challenge are you addressing? For whom? What matters most? This phase takes broad exploration and focuses it into an actionable problem statement.

Develop (Diverge) - Generate multiple potential solutions. Explore different approaches, create concepts, and prototype possibilities. As in Discover, breadth matters - don't commit to one solution too quickly.

Deliver (Converge) - Refine and implement the chosen solution. Test, iterate, and finalize what will actually ship. This phase takes solution exploration and converges on something real.

The two diamonds

The model's power comes from its two-diamond structure:

First Diamond: Problem Space - Discover and Define together explore and then focus the problem. Many teams skip this diamond, jumping to solutions before understanding problems. The first diamond prevents building solutions to the wrong problems.

Second Diamond: Solution Space - Develop and Deliver explore and then focus solutions. This diamond produces actual outputs. But solutions are only as good as the problem understanding from the first diamond.

The connection between diamonds matters. A well-defined problem from the first diamond enables effective solution exploration in the second. A poorly defined problem means the second diamond starts on shaky ground.

Using the double diamond

The framework applies at various scales:

Project level - A major initiative might spend weeks or months in each phase, with formal research, synthesis, ideation, and development stages.

Feature level - A feature might move through the diamonds in days or weeks, with lighter-weight research and faster iteration.

Design session level - Even a single workshop can follow the pattern: diverge to generate ideas, converge to select the best, diverge to develop variations, converge to finalize.

The framework is descriptive, not prescriptive. It doesn't mandate specific activities for each phase - many methods can support each phase. It describes the shape of the process, not the specific steps.

Divergence and convergence

The framework's core insight is the alternation between modes:

Divergent thinking explores possibilities. It asks "what might be?" and values quantity over quality. Brainstorming, research, and ideation are divergent activities.

Convergent thinking makes choices. It asks "what should be?" and values quality over quantity. Synthesis, decision-making, and refinement are convergent activities.

Common failures come from mode mismatches:

Limitations and extensions

The Double Diamond has limitations:

Linear appearance is misleading. Real work loops back and forth. Delivery reveals problems that require new discovery. The phases aren't strictly sequential.

Scale ambiguity means it's unclear how detailed each phase should be. The same model describes multi-year programs and afternoon workshops.

Problem framing is assumed. The model assumes you know what general area to explore. How you decide to enter the first diamond isn't addressed.

Extensions and variations address some limitations:

Triple Diamond adds a phase for understanding context before exploring problems.

Design Squiggle more accurately represents the messy, non-linear reality of design work.

Continuous Discovery applies the diverge-converge pattern as an ongoing activity rather than a project phase.

Despite limitations, the Double Diamond remains valuable for its simplicity. It provides an accessible mental model that helps teams understand when to explore and when to decide, when to widen and when to narrow. That fundamental insight improves design processes regardless of specific methodology.