Innovation & product
Double Diamond
The Design Council's four-stage map of the design process. Two diamonds of divergent and convergent thinking: the first finds the right problem (Discover, Define), the second finds the right solution (Develop, Deliver).
Also known as The Design Council Double Diamond, Framework for Innovation (2019 evolution). First set out by The UK Design Council in 2005; the primary source is cited in full below.
- Format
- Process / loop
- Level
- Product · Team
- Best for
- Understand customers · Evaluate options · Plan execution
- Decision stage
- Diagnose · Explore options · Plan
- Difficulty
- Introductory
- Time to apply
- Weeks to months for a full pass; the model itself can frame a project plan in an hour.
Plate · The model
The components
Discover
Divergent exploration of the problem space: user research, observation and evidence-gathering that questions the initial brief rather than decorating it.
Signals of strength
The team spends time with users before discussing solutions · Findings challenge at least part of the original brief · Evidence is collected wide of the obvious stakeholders
Define
Convergent synthesis of discovery into a sharp design brief: the chosen problem, the people it affects and the evidence behind it. The narrow waist between the two diamonds.
Signals of strength
The brief is rewritten, not merely restated, after discovery · The definition excludes things as clearly as it includes them · Sponsors sign up to the redefined problem before development starts
Develop
Divergent creation of candidate solutions to the defined brief: parallel concepts, prototypes and user testing that let evidence pick the winner.
Signals of strength
More than one concept survives past the first sketch · Prototypes are tested with users, not just reviewed internally · Weak concepts are killed on evidence rather than seniority
Deliver
Convergent finishing and launch of the chosen solution: final testing, production, rollout and measurement, with lessons fed back into future cycles.
Signals of strength
Launch criteria were agreed before the final push · The thing shipped is measured against the Define-stage brief · Post-launch learning is captured and routed to the next project
When it earns its keep
- A project is about to jump straight from a stakeholder's brief to a solution, and you need a structure that forces the problem to be examined first.
- You want a shared vocabulary for design work across a mixed team; the four stages are simple enough for non-designers to hold and use.
- You need to explain to a sponsor why the team is 'going wide' with research or concepts before committing, and when convergence will happen.
- Scoping and budgeting a design or innovation project, since the diamonds mark natural gates for review and re-commitment.
And when it doesn't
- The problem is already precisely defined and validated. Running a Discover phase over settled ground wastes time; start in the second diamond.
- The work is genuinely exploratory research with no delivery intent, where forcing convergence to a defined brief closes options too early.
- Continuous product optimisation with live data. Rapid experiment loops such as build-measure-learn fit better than a staged process.
- You need guidance on what to do inside each stage. The diamonds are a map of the shape of the work, not a method; pair them with concrete research and prototyping practices.
How to run it
Before starting, gather the inputs the analysis depends on:
- An initial brief or opportunity statement, held loosely enough to be rewritten at the end of the first diamond.
- Access to users and stakeholders for discovery research, plus time protected for it in the plan.
- A team able to both diverge (generate) and converge (decide), with agreed criteria for the convergence points.
- Sponsorship that accepts the defined problem may differ from the brief that started the project.
- 1
Discover: diverge on the problem
Open the first diamond. Gather evidence about users, context and the system around the brief through interviews, observation and desk research. The discipline is to suspend the solution, and the stated problem, long enough to see what is actually going on.
- 2
Define: converge on the brief
Close the first diamond. Synthesise discovery into a clear, evidenced design brief that names the problem worth solving and for whom. This is the pivot of the whole model; a weak definition sends the second diamond off at speed in the wrong direction.
- 3
Develop: diverge on solutions
Open the second diamond. Generate multiple candidate answers to the defined brief, prototype the promising ones, and test with users. Working with several concepts in parallel is the point; a single concept 'developed' is just delivery with extra ceremony.
- 4
Deliver: converge on the answer
Close the second diamond. Select the solution the evidence supports, refine it through final testing, and take it to launch, including production, rollout and measurement. Feed what launch teaches back into the next cycle rather than treating delivery as the end.
Reading the result
A redefined, evidenced design brief at the close of the first diamond, and a tested, delivered solution at the close of the second, with clear divergence and convergence gates a sponsor can govern against.
- Judge the project by the quality of its Define stage. If the defined brief is identical to the starting brief, the first diamond probably did not happen.
- The geometry matters: each diamond widens before it narrows. A schedule with no visible divergence, or convergence that never commits, means the shape has been lost even if the stage names survive.
- Expect loops in practice. The Design Council's own 2019 restatement stresses iteration; returning from Develop to Define on new evidence is the model working, not failing.
A worked example
A children's toy manufacturer responds to falling sales of its flagship range
A UK wooden toy manufacturer has watched sales of its flagship stacking-train range decline for three years. The commercial team's brief is 'refresh the range with app-connected features to compete with screens'. Before tooling up, the product team runs the brief through a Double Diamond.
- Discover
- Home visits with fourteen families, retailer interviews and playground observation. The evidence surprises: parents are not asking for connected toys, they are guilt-ridden about screen time and crave short, reliable windows of joint play. The existing range is designed for solo child play, so parents drift back to their phones within minutes.
- Define
- The brief is rewritten: design for twenty-minute parent-and-child play sessions on weekday evenings, where the adult has a real role rather than a supervising one. App connectivity is explicitly excluded; it solves the competitor's problem, not the customer's. The sponsor signs the new brief.
- Develop
- Three concept directions are prototyped in parallel: a co-operative marble-run system with two-person assembly steps, a story-driven building set with adult and child card decks, and a timed challenge range. Six weeks of testing in homes kills the timed range quickly (it created pressure, not play) and shows the marble run holding joint attention longest.
- Deliver
- The co-operative marble run goes to final engineering and safety testing, with packaging redesigned to show an adult and child building together. A staged launch through two specialist retailers measures repeat purchase and gifting before the full trade rollout. Session-length findings from launch feed the next range's brief.
The read. The first diamond saved the company from an expensive app-connected dead end by replacing the assumed problem, competing with screens, with the evidenced one, enabling joint play. The second diamond earned its keep by running three concepts rather than one; the eventual winner was not the concept the team initially favoured. The output is a range with a defensible position screens cannot occupy.
Pitfalls
- Skipping the first diamond because the brief 'is obvious'. The model's main value is forcing the problem to be found before the solution; without Discover and Define it is just a delivery plan.
- Diverging without ever truly converging, so Define produces a vague theme rather than a decidable brief and Develop produces a concept zoo nobody will cull.
- Treating the four stages as a waterfall with sign-offs, when the Design Council itself stresses iteration between and within the diamonds.
- Using the diamonds as the method rather than the map. The stages say when to diverge and converge, not how; teams still need real research, prototyping and testing craft inside each.
- Letting the second diamond quietly abandon the Define-stage brief, so what ships answers a different question from the one the evidence posed.
What the critics say
The tidy sequence misrepresents how designers actually work. Research on design cognition shows problem and solution co-evolve, each reshaping the other throughout, so a model that finishes defining the problem before developing solutions is a simplification that practice routinely violates.
Dorst, K. and Cross, N. (2001) 'Creativity in the design process: co-evolution of problem-solution', Design Studies, 22(5), pp. 425-437.
The Design Council conceded the linearity critique itself: its 2019 evolution wraps the diamonds in a 'framework for innovation' with explicit principles, a methods bank and iteration loops, acknowledging that the bare 2005 model was read as a linear process and gave no guidance on culture or methods.
Drew, C. (2019) 'The Double Diamond, 15 years on', Design Council, Medium, and Design Council (2019) 'Framework for Innovation'.
As a description distilled from studying large firms' design departments, it describes the average shape of past projects rather than prescribing what makes design succeed; the neat symmetry of two equal diamonds owes more to communicability than to evidence about how effort is actually distributed.
Sources and further reading
- Design Council (2007) Eleven Lessons: Managing Design in Eleven Global Brands. London: Design Council.
- Design Council, 'History of the Double Diamond'. ↗
- Design Council (2019) 'Framework for Innovation'. ↗
- Dorst, K. and Cross, N. (2001) 'Creativity in the design process: co-evolution of problem-solution', Design Studies, 22(5), pp. 425-437.