At SAI we have a deep focus on creating engaging and effective user interfaces (UIs) for websites and applications. To quote an overused phrase – “we live and breathe this stuff.” But a recent experience reminded me yet again just how critical user experience is to using technology; and how overlooking one guiding principle of effective user interface design – consistency – can have a substantial negative impact.

 The story begins as my five year old daughter is drinking her evening cup of milk while playing on our family room laptop. You probably see where this is heading, and yes, that cup of milk ends up spilled all over the laptop. Despite my valiant efforts to dry it out, the laptop was beyond repair. So, to replace the destroyed laptop I decided to go with an Ultrabook running the Windows 8 operating system (OS). I figured it would be an easier transition for my wife and kids than going the Mac route since the old laptop ran Windows 7. 

As I began to set up the new laptop I expected it to be an easy transition with a minimal learning curve from prior experience with new Windows versions. The interesting thing about Windows 8 is that it basically combines two separate user interfaces – an updated version of the familiar Windows desktop interface, similar to Windows 7 or XP, and the new Metro, or “Modern” UI, which is based on the Windows Phone interface.

My first task setting up the laptop was creating user accounts. I opened the familiar User Accounts Control Panel applet in the desktop interface and noticed that I could edit or delete users, but the option for adding new users was missing. After poking around a few more minutes and getting somewhat frustrated by my inability to complete a very basic task, I turned to Google. From my Google search it became clear that many others ran into the same roadblock. I learned that to create users I had to use the Settings app in the new Metro UI.

I then created the users – easy enough – and figured this must be the new way to manage users and the Control Panel applet is just there for backwards compatibility. That is until I needed to edit a user. I went to the Metro app where I created the user accounts and found that this app only allows me to add users, but to edit or delete users I have to use the Control Panel applet in the desktop interface. This approach didn’t make much sense to me from a usability perspective – why two separate UIs for a related set of tasks.

I ran into similar issues working with the new Internet Explorer (IE) 10 browser. Windows 8 has two versions of IE 10, one is a Metro app, and the other is an application in the desktop interface that looks and functions very much like IE 9 on Windows 7. The two versions of IE 10 look and behave differently from one another, and certain functions, like editing settings or your browser home page can only be done in the desktop version of IE. Again, this didn’t seem to make much sense.

The above examples proved to be a common theme when working with Windows 8, some tasks were performed in the Metro UI, some in the desktop UI, and some could be completed in either. Even when a task could be completed in either UI, the way that task was completed in each differed, considerably in some cases. I found this to be very jarring, constantly switching between two UIs that looked and behaved quite differently to complete common tasks.

Although this post may be starting to sound like a rant against Windows 8, that’s not the intent. I’m just illustrating how trying to combine two disparate user interfaces significantly detracts from the overall end-user experience. Windows 8 users are forced to repeatedly adjust their mental model of how to interact with the OS depending on which user interface they happen to be working in; understandably leading to frustration.

I think that individually both the desktop and Metro UIs are quite usable. The message here is that when you combine these two very different UIs into the overall Windows 8 interface, the end result is a rather jarring and often frustrating experience for end users.

Now circling back to our topic – why consistency is an important aspect of usability. The root cause of usability issues in Windows 8, in my humble opinion, is the lack of consistency created by forcing users to constantly switch between the Metro and desktop UIs.

The takeaway for UX professionals is that we need to focus on the totality of the experience when designing a user interface. A well designed UI or set of UIs that are part of a larger application are not effective if they look or behave differently than the rest of application. An effective experience provides users with a predictable UI, one that does not require constant relearning. When designing, we too often tend to focus on the trees rather than forest, especially when building UIs for new features in an application. The key is to step back and to consider how what we’re designing aligns with the greater whole, rather than just focusing on addressing the task or feature at hand.