UCD, UX, Usability – So What’s the Difference?

There are probably thousands of articles out there covering aspects of this topic, but I’m going to try to boil this down to my basic understanding of the differences.

What is User-Centered Design (UCD)

UCD is a philosophy that puts the user in the center of the design and development process.

Illustration of user-centered design process

As you can see in my lovely Word illustration above, if we split the creation of a website or application into phases, we end up with:

  • Research
  • Concept
  • Design
  • Development
  • Implementation.

In a UCD approach, solutions are evaluated against user and business goals, improvements are made and the new solutions are evaluated again. It is an iterative process involving users, stakeholders and all members of the design and development team. Now, notice that I said user and business goals. Both of these are important in producing a successful product. The key is in identifying how these goals align to deliver value to both the end-user and the business. The value is never the technology, but what the technology enables the user and business to do.

Let’s look at some of the user research and UX methods used in each phase of the UCD process.

Research> Concept> Design> Development> Implementation>
Stakeholder interviews
Competitive Analysis
Focus Groups
Ethnographic studies
Field Studies
Task Analysis
Diary Studies
Desirability Testing
Usability testing
Card Sorts
Information Architecture Flowchart
User Stories
User Interaction Flowchart
System Interaction Flowchart
Content Inventory
Content Maps
Accessibility Planning
Paper Prototypes
Interactive Prototypes
Desirability Testing
Usability Testing
Usability Testing
Bug Testing
Content Creation
Usability Testing
Bug Testing
Post-Launch Surveys
Metrics to Demonstrate Improvements/ Success
Continued User Research

What makes a product usable?

In a great article called “Using the 5Es to Understand Users,” Whitney Quesenbery represents the five dimensions of usability as:

  • Effective
  • Efficient
  • Engaging
  • Error Tolerant
  • Easy to Learn

Although these may be covered in Quesenbery’s dimension, I would also call out a few of Sabina Idler’s 5 Principles of Usability:

  • Accessibility
  • Credibility
  • Relevance

The balance of these within a product offering depends upon both the user and business goals.

What is the difference between user-centered design, usability and user experience?

  • User-Centered Design is a philosophy or approach to the design and development process.
  • User Experience is about the value you are delivering at every point that the user touches a product. This value must align with user and business goals and provide a positive experience on an emotional, social, cultural, psychological and physiological level. In User Experience Design, you find the alignment in the user and business goals and return to these iteratively during the UCD process, all to create the value proposition which will shape the overarching user experience.
  • Usability is specifically focused on the interface of a product and whether it is easy to use, easy to learn – all the things listed in Quesenbery’s 5Es. Usability testing allows us to construct task-based assessment to evaluate these dimensions of a product.

Helpful Resources

What is User Experience Design?

Using the 5Es to Understand Users

The Definition of User Experience

5 Principles of Good Website Usability

In my next posts, I’ll start to cover some of the user research methods outlined above.