Monday, June 21, 2010

Bandwidth issues - why they're a problem

As ever, a brilliant article on website usability from Nielsen that has ramifications for elearning.

In the post simply entitled Website Response Times Jakob Nielsen points out that although increased bandwidth has largely eliminated the old drag of image sizes, responses times should still be given thought in the design of websites in the era of ubiquitous broadband.

The article cites common problems as being "complex data processing", eg lots of server-side activity, be it script or database activity, and slow "widgets" or too many of them.

With LMSs, especially those adopting more "web 2.0" features, the temptation to load up on widgets to provide the rich opportunities for social interaction that learners may be looking for is a risk. Especially if the server setup it is delivered from is less than optimal. Of course, the far greater hazard from the point of view of elearning is poorly produced Flash content. In a post from last year, Gavin Hess muses on the fact that many "rapid" tools actually save time only for the producer - the product they produce not always being the fastest.


Still, what is the impact of a delay? Nielsen summarises the impact of increasingly longer delays:
  • 0.1 seconds gives the feeling of instantaneous response — that is, the outcome feels like it was caused by the user, not the computer.
  • 1 second keeps the user's flow of thought seamless. Users can sense a delay, and thus know the computer is generating the outcome, but they still feel in control of the overall experience and that they're moving freely rather than waiting on the computer.
  • 10 seconds keeps the user's attention. From 1–10 seconds, users definitely feel at the mercy of the computer and wish it was faster, but they can handle it. After 10 seconds, they start thinking about other things, making it harder to get their brains back on track once the computer finally does respond.
 What will happen if this covenant is broken? Well, Nielsen is worried about lost sales and conversions. From an elearning point of view we can assume lost attention will result in poorer retention, less chance of completion (if that's an important statistic for you) and a generally less positive reception to your courses.
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