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Strategic insights
Usability by Hand, AJAX and Efficiency

Written by on April 5, 2006

Manipulating your computer is, in general, not a very efficient way to work. Using the keyboard to - say "print the first page, in 4 copies, of a document", involves around 6 to 21 keystrokes. Using the mouse is not much better.

This inefficiency motivates many companies, and developers to think of new approaches to computer interaction. Microsoft Research, among others, has long been exploring possibility of using hand gestures. It does have a lot of potential, but if it is not done right it could be a very bad approach.

It reminds me of Douglas Adam's "The Hitchhiker's Guide to the Galaxy", where this interaction method is commonly in use.

"A loud clatter of gunk music flooded through the Heart of Gold cabin as Zaphod searched the sub-etha radio wavebands for news of himself. The machine was rather difficult to operate. For years radios had been operated by means of pressing buttons and turning dials; then as the technology became more sophisticated the controls were made touch-sensitive - you merely had to brush the panels with your fingers; now all you had to do was wave your hand in the general direction of the components and hope. It saved a lot of muscular expenditure of course, but meant that you had to sit infuriatingly still if you wanted to keep listening to the same program."

- Douglas Adams, The Hitchhikers Guide to the Galaxy

We can safely say this approach are not what we want, and I think that hand gesturing in particular has a very limited usability on desktop computers.

The reason is GOMS and Fitt's law - the old formulas for measuring efficiency in keyboard handling and mouse movement. A gesture like waving your hand takes considerably longer than clicking your mouse. So in many cases hand gesturing is a rather inefficient way to use a computer.

Web 2.0 and AJAX interactions

This is comparable to the interactions we see today with "Web 2.0" and AJAX.

Almost everyday a new fancy navigation method emerges. We have seen a huge amount of drag and drop [insert anything here]. We have seen several methods of interaction based on the position of the mouse. Some works, some are very interesting, but most of them directly kill your efficiency.

Take drag and drop shopping carts, where you drag product in or out of the space reserved for your cart. This sure looks fancy. But, it is more than 1000% slower to drag and drop, than to simply click an "Add to Shopping Cart" button. Specifically it takes 0.2 seconds to click on any target, and 2.4 seconds to drag and drop.

This is true for about 95% of all new interaction methods build under the "sphere" of Web 2.0 and AJAX. In an attempt to create fanciness some forget the basics. In an attempt to impress some take away the only thing that we cannot do without - efficient usability.

I am all for the invention better interaction methods, but reinventing the wheel and making it square are not a very usable approach. We need to remember that better interaction comes from removing as much of it as we can.

You need to lower the number of times you have hit a key on your keyboard, or move/click with your mouse. AJAX can help you do this, because it can be used to automate tasks that previously had to be done manually.

The key to success is to use the new technologies to create a better, faster and more efficient user experiences - not to impress or show-off.

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Thomas Baekdal

Thomas Baekdal

Founder of Baekdal, author, writer, strategic consultant, and new media advocate.


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