The Usability of Interruptions

There was recently a very interesting seminar at Stanford University about interruptions - specifically how to make better reminders and notifications in your products.

We all know that notifications are disrupting the flow of our work, and that we should minimize their use. In my point view disrupting notifications should only be used when:

• Something catastrophic is about to happen, and your work will be lost if you do not act immediately.
• Important events is about to take place, and the computer can sense that you are not aware of it.

Emails and 99% of all security notifications rarely fall into these categories. These, and similar cases, should instead be designed to be non-interruptive (that is when they do not pop-up or flash into view)

The main point of seminar was that they have researched the effect of being interrupted at different times. They found that it is much less intrusive if you are interrupted between tasks. You should hence not interrupt people when they in the middle of something (makes sense for a number of obvious reasons).

Specifically they found that disruptions between-task causes:

• 47% less anxiety about being interrupted
• 36% less annoying
• 50% less errors in the following tasks
• 3% to 27% less time to regain focus

Note: the figures are the percentages between being interrupted in the middle of something vs. in-between tasks. They did not study what the effect would be if you was not interrupted at all. I would imagine this to be rather significant.

This is very interesting - and the numbers are huge. 50% less errors is enough for anyone to think twice about how you are interrupted.

See also:

• Multitasking is not good for anyone, Baekdal.com (April, 2007)
• Security is the Biggest Threat to Security, Baekdal.com (September, 2006)