Multiple Devices. Cloned Experiences?

Usability Engineers and Technologists who think they understand the basic principles of User Experience Design often brag that their latest UI is one that can be rendered consistently from device to device. They'll go on to state that a consistent User Experience across devices is "best practice" for UX Design.

If their interpretation of that "best practice" is the replication of a user interface across multiple types of devices and form factors, I say they are missing the point of User Centered Design..big time!

Multi-platform, brand consistency is, indeed, important, in terms of the aesthetics, personality, and the taxonomy of products, services, and content. But that doesn't equate to the need to present the user the same user interface, or even product and features, from one device to another. This practice implies that the Design team has no idea how different devices may be used differently by end-users.

It is necessary to extend our behavioral personas, which may focus on single device usage, or a "single scenario" involvng one device, to include scenarios involving multiple devices...even multiple, concurrent, device usage.

Mobile and Desktop = Solitary Experiences
It is helpful to understand the number of people likely interacting with the user interface, when designing the UX for a device application. For example, a mobile phone, desktop computer, or laptop, probably doesn't get passed around too often. In the case of the mobile phone, a device that could easily get passed from one individual to another, it may be odd to think of this device as a "solitary device", yet the thought of another individual using my smartphone feels like an uncommon use case.

Also important in determining whether or not an application may be shared, is the physical size of the device that the app UI sits atop.  If the application is intended for desktop computer or laptop, then the bulkiness of these devices, and the likely context of their usage, influences our decision to design solitary user experiences for them.

Tablet = Sometimes Solitary, Sometiomes Shared Experiences
The tablet provides an ideal form-factor to share an experience with multiple end-users. A simple scenario is a well-designed, television remote control application that can be passed from one member of the family to another, while watching TV, in the living room. A second scenario is a digital magazine application that is ideal for sharing.

In the first scenario, the TV remote app, we may design the User Interface to accomodate multiple, end-users. We may do this, by introducing sub-accounts that store bookmarked channels based on the preferences of each, individual in the household. The important thing to note, is that the UI may need to present different data, based on who is using the device.

In the second scenario, the digital magazine, we may still design the UI to target a single, end-user, at-a-time, even though we know the device may get passed around.

Mobile = Different Use Cases than Desktop
A business should focus on the differences of a digital UX, versus the consistency of the UX across devices, when designing a mobile application. Given the context of usage of a mobile device, as well as the small screen form factor, it makes no sense to "miniaturize the desktop UX", and shove it into a mobile app.

End-users have their mobile devices wherever they go, but they use mobile apps for different reasons than desktop apps. When designing an application for a mobile device, it is important to think of one or two, likely, high-priority use cases for that application, in a mobile context. Don't try to replicate every feature in your desktop application for your mobile app. Document likely mobile scenarios, and use cases, first, before tackling the user experience design of your mobile application.

Conclusion
There's alot of work to be done, prior to launching a single digital application in your total digital ecosystem. It involves consideration of your end-user and consumer behavior across every digital touchpoint, throughout the lifecycle of their interaction with your brand (which, hopefully, has no end-point). There is no simple, "best practice" to suggest that every user interface and product feature has to be the same on every device. Devices are components of a tool-box to aid the user through her journey, not a cloned tool, of various sizes and form factors, that has a single-minded, repeated function.