What is user-centred design (UCD)?

In short

In user-centred design, decisions rest on knowledge about users. According to the Interaction Design Foundation, designers focus on users and their needs in every phase of the design process.

ISO 9241-210 calls the same approach “human-centred design”. The 2019 second edition of the standard replaces the first edition from 2010. Its roots go back to the older ISO 13407.

According to the introduction of the standard, the aim is to make systems usable and useful. The way there is by focusing on users and their requirements.

The six principles of ISO 9241-210

The standard doesn’t assume any particular design process. It can be built into very different approaches, such as the waterfall model. Whatever the process, it recommends these principles:

1. The design is based on an explicit understanding of users, tasks and environments.
2. Users are involved throughout design and development.
3. The design is driven and refined by user-centred evaluation.
4. The process is iterative.
5. The design addresses the whole user experience.
6. The design team includes multidisciplinary skills and perspectives.

The standard counts an incomplete or inappropriate understanding of user needs among the major sources of systems failure. I also consider it the most expensive mistake. The screen is carefully designed, but it answers the wrong question.

The process: a four-step cycle

The standard describes four activities. I call them, for short, understand, define, design and evaluate.

Each step has a tangible output. According to the standard’s examples, the first step produces user group profiles and personas. The design step produces prototypes. One output of the evaluation is the usability test report.

An example scenario

A made-up example: a city water utility is redesigning the screen for paying the water bill. The team’s first idea is a big “Check amount due” button on the home page.

Understand. The team talks to ten people at the customer service centre. Most don’t know their account number and only have an old paper bill. Define. The requirement becomes clear: people must be able to find the amount due even without an account number.

Design. The team designs two things: a graphic showing where the number is on the bill, and a lookup by meter number and address. Evaluate. In the test with five people, two miss the meter number lookup. The team moves the option up front and repeats the cycle.

The big button idea stayed. The real work was making sure the person doesn’t get stuck on the next screen after the click.

Often confused: doing what users ask for

User-centred design doesn’t mean building every feature users wish for. Users describe the problem well; the team develops the solution and checks it with users again.

Then there is the misconception “We ran a survey, so we are user-centred”. The standard speaks of active involvement. Users can take part in the design, act as a source of data or evaluate solutions.

Related terms

• Mental model: the picture in users’ heads of how a system works.
• Information architecture: organising content so users can find it.
• Wireframe: the first rough sketch in the design step.
• Nielsen’s 10 heuristics: a checklist often used in the evaluation step.