CX, UX and Usability -A Nested Relationship

For the design of products and services, the terms Customer Experience (CX), User Experience (UX) and Usability are critical to get right if you want to work Strategically with UX. However, many design teams use the three interchangeably, which can lead to confusion or even contradictions that can negatively impact the design process. To clear this up, our series on Strategic UX begins with providing terminology that lets you work effectively with your team.

✎ By Rune Nørager, April 2020

Key takeaways:

– An operational account of the relationship between CX, UX, and Usability

– From one kind of usability to six

UX and Usability - Different or the Same?

To begin, let us focus on User Experience (UX) and Usability. We will integrate them with customer experience (CX) later.

Please take a moment to reflect on what you see as the differences between UX and usability. 

For many, the answer is that Usability is about the practical stuff, i.e. whether something works. In contrast, UX has to do with how design makes users feel, i.e. the “emotional stuff”. According to this view, UX and Usability are two different things. 

We disagree.

Instead, we see them as two different levels of abstraction with Usability being nested as one part of UX. And on that note, we see Usability as not only one thing, but several.

This approach to UX and Usability was outlined by Morten Hertzum in his article Images of Usability. In his article, Hertzum introduces six different types of Usability as potential drivers of quality in the user interface of technology. These six types are: Organisational, Cultural, Universal, Situational, Perceived, and, finally, Hedonic usability. Each usability type is linked to a strong body of evidence-based research, tools, as well as metrics for measuring them. The figure on the right elaborates each type of usability.

Importantly, the “emotional stuff” is only one of six types of Usability, Hedonic Usability, rather than being synonymous with UX.

So, in our view, UX is the general term for the experience users have when interacting with products, and this experience can be broken down into six types of Usabilities.

Factoring in CX

With UX and Usability defined, we can now define add our definition of Customer Experience (CX).

Just as UX is constituted by several Usabilities, CX should be considered as constituted of the different UX touch-points of a customer journey. This is illustrated in the model to the right.

The understanding that UX is nested in CX seems to be widely accepted in the design community. By nesting the six types of Usability inside the UX, Usability should also be seen as part of the CX.

A Nuanced Design Strategy

The proposed definitions of CX, UX and Usability provide a nuanced account of one part of UX via the six individual Usability types.

For any given design project the challenge then becomes to understand and define what mix of usabilities that are the right to meet particular user needs. Indeed, with the approach, it can be considered part of a design strategy to consider which Usabilities to prioritise and in which way.

This adds a much-needed balance to design projects where the primary strategic focus tends to be in the raw functionality linked to the utility of the product. 

Besides Usability, which resides in the User Interface, UX also depends on how well the product functions. We call this its Utility. Therefore, the value of UX is a combination of the its Usability and its Utility. This is commonly presented via the following equation:

Usability + Utility = Usefulness

At Design Psychology we use a similar equation, which we call the User Experience Value Equation, or UX-ValuEQ for short, to explain the business value of UX to our clients.

In comparison with the original equation:

usability + utility = useful

we have replaced the summation with multiplication:

usability × utility = useful

We did this to underscore the importance of the user interface: Good Usability is not simply an added bonus to the Utility - it plays a vital role in realising the Utility for the user. If Usability drops close to zero, the actual Utility of the product also drops to zero for all but the most advanced users.

This further means that testing with skilled users can be a liability, as it obscures the important role the user interface plays to your business. We have covered this topic earlier in the article linked her: ☞ “Usability Dieselgate”.

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Next Steps