What’s different about mobile UX design?

I’ve been fully focused on mobile UX design for about a year now, after a number of years of doing mostly web and desktop UX.

Here are a few things I’ve learned along the way about how mobile UX design is different:

1) “Mobile” can be misleading – it describes one of several possible contexts for using a smartphone or tablet.

A recent quote from Barbara Ballard says it best – “Fundamentally, ‘mobile’ refers to the user, and not the device or the application.”

Tablet apps especially are as often as not used in a context that’s not truly “mobile”.

2) Consistency with the overall device experience is more important than consistency across platforms.

The “uncanny valley” that results from porting an app design straight from one platform to another, or attempting to mimic native UI elements in a web app as closely as possible, is especially to be avoided.

3) Mobile UX design is, in many ways, an act of curation.

When designing for mobile platforms, one has to be much more careful about selecting content and interactions for a given screen or app state than on the web or desktop.

Global navigation is often limited or absent. Menus, toolbars, and other navigation elements usually have strict limits on the number of items they can provide. So ensuring that users have access to all the functions they need (and none they don’t), and that they can find their way out of a given app state, is crucial.

4) Just because a platform makes an interaction possible, or provides a native UI element for a particular purpose, doesn’t mean you should use it.

For example, I’ve seen the “detail disclosure” button, a key affordance in list views on iOS, perform poorly in usability testing, even with experienced iOS users. Same for a slideable top navigation on Android – an often used element, but a classic example of “mystery meat” navigation.

It’s still early days, and no one, including OS designers, really has mobile UX best practices fully figured out yet. When in doubt, testing is always the best way to validate design choices.

5) Unlike web apps, mobile apps are not amenable to “design by perpetual beta” or “design by A/B testing”.

The effort required to download an app update from the app store, and the fact that app stores provide easy access to user ratings and reviews, mean that a poorly designed new app or update, once released into the wild, can easily invite a huge user backlash.

Jakob Nielsen’s recent Alertbox on the WSJ app is a great case study of how one poor design decision can utterly sink an app, even one from a major brand with a built-in loyal audience. This, again, reinforces the importance of testing with representative users before an app ships.