How tiny flaws in the user interface can lead to negative user ratings

UI professionals keep repeating it: usability is a key to success. One of the most prominent examples is the iPhone 2G. When being released in 2007 it lacked lots of features that were already present in other devices, such as 3G networking, GPS receiver, or a camera. But it arguably it was just the easiest to use phone around then.

However, even when the system is easy to use in general, small usability issues can have huge negative effects. This post reports from an illustrative case that occurred in my research group. Currently, we are working on an Android application called PocketNavigator, which is basically a map-based navigation system.

While the core of the application seemed to be sufficiently easy to use, a rather small ambiguity in a secondary feature brought us bad user ratings.

Due to many requests we added a view that allowed searching for addresses. It provides a text field, where users can enter the address, e.g. “Berlin” or “1 Broadway, New York”.

The address search view as the user initially sees it.

For convenience, we stored the last 5 searches and made them accessible through a drop box. To not have to deal with an empty drop box when the application was just installed we initially filled it with five city names.

The address view with the unfolded drop box showing the name of the five initially stored cities. — The initially present cities.

After having released the address view in an update, we faced negative comments in the Android Market saying “only works in five cities”. We could not make sense of this until our colleague complained about the same issue. The UI was giving the impression that the text field only allowed to enter a street and the drop down box had to be used to select the city. So some user’s did not know they could enter any address including a street and a city in the text field.

We addressed the problem by slightly revising the user interface. First, we changed the labels to stress that the user could either enter an address or choose a previously entered one.

Second, the drop box would now be filled with complete addresses, such as “Tiergarten Berlin” or “10 Downing Street, London” to demonstrate what types of searches are possible.

With these countermeasures we hope to avoid such confusion in the future.

In summary, this case is a nice example of how a small usability issue can lead to a bad overall impression of an application. It reinforces that ensuring a good usability should never be neglected when developing an application for a wide audience.

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