Definition of Usability
I saw a chart the other day being used to describe usability and it was one of the most concise images on the importance of usability I have ever seen, yet the presenter did not really explain the chart which was unfortunate. I did not notice a reference source on his presentation yet I know it came from other sources (which is why I am not citing the presenter directly). So in the spirit of research (being information from many sources) I’ll attempt to review the points the chart was making.
The definition of Usability is a time based definition. Initially DISCOVERABILITY and CONSISTANCY are most important. How easy is it for an application user to discover functionality without resorting to manuals and training materials. When moving from area to area of an application how consistant is the presentation of the user interface so that relearning leverages that consistancy. Microsoft is a classic example and more an more non-Microsoft applications boast of the “Outlook” interface. But that interface is not best for all systems - so when looking at Usability - look for discoverability and consistancy initially.
The problem however, is that the definition of usability often stops there - and later when the honeymoon is over, the other components of usability become more evident. After the initial learning - how much is EFFICIENCY and CAPABILITY expanded. After discovery - do efficiency improvements continue or go flat? Can you expand your use of the tools thru leveraging the additional capabilities of the tool beyond the initial need? These aspects of usability are not readily addressed in product demos and are not realized until the user has completed the honeymoon or nightmare of the first side of the usability question.
In the best of both worlds you would want to look at solutions that have the near term and longer term definitions of usability being satisfied. In reality it may be a compromise - The paradoxical definition of usability explains why difficult to learn systems are adopted and have productivity gains dispite the lack of discoverability and it also explains why highly discoverable systems become flat for efficiency gains downstream yet may be widely adopted by the masses.
So when you go into your system selection process with Usability criteria - be sure to include all 4 components of usability - not just how easy is it to use initially. Again look for DISCOVERABILITY, CONSISTANCY, EFFICIENCY and CAPABILITY. When you have all 4 you have a system that will serve you as a longer term solution.
Copyright 2007, LR Hirr, All Rights Reserved
