Research the users and the business, define the problem and how success is measured, sketch several solutions, prototype the strongest, test with five or so users per round, and hand over annotated screens and a design system. The Double Diamond calls these Discover, Define, Develop and Deliver. Build accessibility in from the first wireframe.
This is the main guide in our UX series. The guides below cover auditing an existing product, software products, business buyers and phone apps.
UX and the Double Diamond
Nielsen Norman Group defines user experience as all aspects of a person's interaction with a company, its services and its products, broader than the interface alone. Our guide to UI vs UX design explains the difference.
The Design Council's Double Diamond, first described in 2003, draws the process as two diamonds: the first widens to Discover the problem and narrows to Define it; the second widens to Develop possible answers and narrows to Deliver one. The six steps below follow that shape.
Step 1: Research
Research finds out who the users are, what they are trying to do and what gets in the way. Four sources:
- Stakeholder interviews: what the business needs, the constraints, and how success will be judged.
- User interviews: five to ten people per user type in our own working practice, about their work.
- Analytics and support data: where people drop off, what they search for, what they complain about.
- A review of the current product, if there is one, against usability heuristics.
Step 2: Define
Turn research into a short written brief: the users and their main tasks, the problem in one or two sentences, the measures of success (task completion, time on task, conversion, support tickets) and what is out of scope. Personas and step-by-step maps of each user's path help when they come from the research; invented ones mislead. Everyone signs off the brief before solutions start.
Step 3: Ideate and structure
Sketch several ways to solve the problem before choosing one. Map the information architecture (what goes where and what it is called), then the main user flows step by step. Low-fidelity wireframes come next: boxes and labels that show layout and content without visual design, so feedback is about structure.
Step 4: Prototype
Build a clickable prototype of the main flows, enough to test. Apply the visual design once the structure holds. Use or start a design system: reusable components, styles and rules, so screens stay consistent and developers build each part once.
Step 5: Test
Put the prototype in front of real users and watch them try the main tasks. Jakob Nielsen's article Why You Only Need to Test with 5 Users (2000) argues for small rounds of about five users, repeated after each change, over one large study. Alongside testing, review the screens against Nielsen's 10 usability heuristics (1994, last reviewed January 2024), such as visibility of system status, consistency and standards, and error prevention.
Check accessibility in the same rounds. WCAG 2.2 is the current W3C Recommendation, and US rules such as ADA Title II cite WCAG 2.1 AA, which 2.2 includes; its Level AA criterion 2.5.8 sets a minimum target size of 24 by 24 CSS pixels for pointer inputs, with exceptions. In the US, the Department of Justice's ADA Title II rule (April 2024) requires state and local governments to meet WCAG 2.1 Level AA, from April 2027 or April 2028 depending on size. This is general information, not legal advice.
Step 6: Hand over
Handover is where most design value is lost. Developers need:
- Annotated screens for every state: empty, loading, error, success.
- The design system: components, colors, type, spacing and their rules.
- Interaction notes: what happens on tap, hover, swipe and keyboard focus.
- Accessibility notes: contrast, labels, focus order, target sizes.
- Design review in build: designers check each built screen against the design.
How long the UX process takes
It depends on scope. A focused redesign of one flow can run research to handover in a few weeks; a new product usually runs research and definition over several weeks before prototypes, then continues in cycles alongside development. Time saved by skipping research is usually spent later on rework.
Common UX process mistakes
The faults that cost the most rework:
- Starting with visual design. Structure and flows come first.
- Asking users what they want. Watch what they do.
- One big test at the end. Small rounds early catch problems while they are cheap.
- Accessibility as a final check. Build it into components from the start.
- Handing over pictures. Developers need states, rules and a design system.
Conclusion
The UX design process runs research, define, ideate, prototype, test and hand over, which the Double Diamond groups as Discover, Define, Develop and Deliver. Test in small rounds of about five users, check screens against usability heuristics and WCAG 2.2, and hand over annotated screens and a design system so what gets built matches what was tested.
PromotEdge International is an international strategy, technology, marketing and design company, and our delivery team is in India. Our UI/UX design team runs this process for SaaS products, apps and websites, and our UI/UX designers can join your team on retainer. We travel to our clients every 3 to 4 months.
The guides in this series
This is the main guide in our UX series. Each guide below goes deeper on one part and links back here.
- UX audit checklist: what to check in an existing product before a redesign.
- SaaS UX design: onboarding, dashboards and settings that work.
- B2B UX design: designing for buyers, users and approvers.
- Mobile app UX design: guidelines for thumbs, small screens and interruptions.
Facts we rely on: see our company facts for what we state about ourselves and where each fact comes from.