Friday, August 31, 2007

Usability and learnability

Designing for usability vs. learnability ...

"The difference between usability and learnability is something that always sticks with me from Joel Spolsky's brilliant User Interface Design for Programmers. He makes the point that when people talk about software usability they quite are often referring to learnability, or how easy it is for a new user to learn how to use an interface. Confusing the two can be bad because learnability is not always the most important part of UI design.

Anyone that uses a command line interface knows how powerful it can be, and indeed for many tasks command lines are simply the best interface. It's rather like the difference between becoming fluent in a foreign language or gesticulating your way by. When holidaying in a country where you don't speak the native tongue, simply pointing to items in a shop or restaurant is much easier than learning the whole language - but if you live in a place for any length of time you will soon find it frustrating and much quicker to get what you want by speaking at least some of the lingo. This isn't to say that hand/mouse waving isn't still appropriate in many situations but just that learning how to communicate in the local language can make your life in Computerland run much more smoothly.

In software we would tend to regard a GUI as more usable than the command shells of power users. The GUI is easier to learn but it isn't necessarily the best tool for the job. A power user might learn keyboard shortcuts or change the file extensions of 100+ photos with a single shell command instead of clicking and renaming each individually with the mouse. Shortcuts like these are invaluable to anyone that uses a computer interface on a daily basis.

The above are common examples where there is a so called user-friendly and power user approach for the same task. However what tack do you take on designing an usable interface when the underlying process is inherently complex? The risk is you are either going to overcomplicate the interface, thus reducing the learnability, or annoy experienced users by making them jump through hoops around an overly simplistic GUI as they try to find advanced features that have been tucked away."    (Continued via The Bug-eyed Chronicles)    [Usability Resources]


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