Updated: Dec 16, 2019
Consistency is fundamental to good UX design. It helps users learn and predict what’s going to happen. It builds confidence from users in the things we create. I’ll look at the benefits of consistent design and the key things to consider.
What is consistency?
Consistency in UX design is the extent to which we maintain a consistent way of communicating with our user. Lines of communication are made easier when the design components we use maintain the same appearance, meaning and functionality. This enables users to learn and understand what we are trying to say more easily.
For example, if our interface includes a ‘back’ button that takes the user to the previously visited page when pressed, then that button should do the same thing wherever and whenever it appears. That way, the user will know what to expect.
Consistency is not necessarily isolated to one product or device. As much as possible, UX components should look the same across devices and a family of products. There should be strong usability reasons and clear visual cues when deviating from consistency.
For example, Apple has rules regarding the appearance of UX components. This means that they are consistent across devices, even though the spacing and number of menu items per line has to vary to maintain usability.
In the same way, UX components and controls should behave the same across devices and a family of products. For example, as a user of Adobe, it baffles me why the default pan/zoom controls are not common across applications i.e. Illustrator, XD. This causes errors and frustration when switching from one product to another.
What are the benefits of applying consistency?
Consistency increases predictability and enables users to transfer knowledge to new contexts. In other words, the user learns how to interact with one element, then when they encounter a similar element, they instinctively know what to do because it is familiar to them. This decreases the time and effort required by the user to learn how to use our interface and means that user interactions are more intuitive.
If an interface behaves in a predictable manner, the user feels more confident in engaging with it because they know what will happen in response to their actions.
Similarly, consistency is likely to build trust in the design, reassuring the user that there will be no unpleasant surprises. Ensuring consistency across multiple platforms (e.g. iOS, Android) and form factors (e.g. TV, desktop, tablet, mobile) will help to secure brand trust and credibility.
Consistency means that users have to think less, so they are able to complete tasks more quickly and with a reduced likelihood of error.
Keeping the development team happy
A happy byproduct of using common UX components that behave in the same way across an interface is that these components can be reused. This reduces development time and cost. Everyone’s a winner!
How do I ensure consistency?
Creating and enforcing a set of design rules or a style guide for all designers to follow helps to drive consistency. Depending on the size of the project, consider more detailed pattern libraries (such as those for iOS and Android).
As a minimum, your style guide should support these types of consistency:
Maintaining high visual consistency not only means that your interface will look more professional, but also ensures that users know what to expect to see and where.
Design rules should clearly define how the following should be implemented across the interface:
Font style and size
Spacing and padding
Animation and screen transitions
For example, Audi have defined each of their icons in terms of style, lineweight, etc., so that they maintain the same appearance across vehicle models. It also creates a harmonious experience within the vehicle: the UX feels like it has been designed by one person.
Behavioural consistency increases the learnability and predictability of your interface. Items that look the same should behave in a similar way. For instance, there should be consistent mapping between visual cues and the direction in which lists scroll.
Take Netflix as an example. The user can scroll vertically to search for a category, then scroll horizontally to search within a category. In both cases, scrollability is conveyed to the user through the display of partially visible items at the edge of the screen.
The lists behave in the same way across different devices, reinforcing familiarity and predictability.
Design rules should define the behaviour of:
Dialogues and any interactive banners, pop-ups or notifications
Elements with specialist functions (e.g. ‘back’ buttons)
Material Design go into a lot of detail regarding UX components and their behaviour. For example, they define what selection controls are and how they should be used in different contexts etc.
This gives designers precise rules for what to use and when. In turn, this provides users with a consistent experience across different products.
Feedback is a way of communicating to your user that something is happening, has happened or is about to happen. Like all communication, it needs to be consistent to aid learning and understanding.
For example, there should be a consistent mapping between visual appearance and button state (e.g. whether they are active, inactive or currently selected).
Design rules should define how all sensory feedback should be implemented (e.g. visual, auditory, haptic) and should include:
Using consistent language (written and auditory) will give an integrated feel to your product and also helps users to interpret content correctly.
Poor consistency runs the risk of creating confusion, for example, by using different terminology to represent the same thing or by using the same terminology to represent different things.
The language used will vary according to the brand and target market, but the need for consistency still applies.
To ensure the user will be provided with a clear and coherent message in the same ‘voice’, design guidelines should include:
Use of jargon, acronyms and abbreviations
In the context of UX, familiarity does not breed contempt! Rather, it installs confidence and reassurance in the user. Having a consistent experience increases predictability, therefore reducing the need for learning and propensity for error.
Applying a set of rules for designers to follow will promote consistency. It will save time and money, but more importantly lay the foundations for a great user experience, keeping your customers happy.