[Sigia-l] Skill based interfaces (was Coat Hanger Usability)

[Anne Miller]

>The danger you have with using user profiles here is the user will have
different levels of skill but still require a  constant and near invisible
interface - but, as with a guitar and car - the feel if needs to be right.

I think you're confusing two different concepts here these being 'skill' and
'expertise'.

Skills can be defined generically for example a pitcher takes up a set
position on a pitching plate, signals the catcher, goes into a windup,
releases the ball. This very roughly defines the skill of pitching
softballs.  Skills-based activity generally involve manual or motor
performance. Other modes of performance are rule-based performance - the
degree to which an actor knows and can follow a set sequence of activities
and knowledge-based performance - the degree to which an actor can draw on
deeper knowledge including first principles about the domain of interest

Expertise is the degree of automaticity with which a skill, or rule is
executed, or the breadth and appropriateness of knowledge bought to bear on
the situation. An expert has high levels of skill/rule automaticity and
breadth of knowledge. When experts perform they do so effortlessly, with
minimal cognitive involvement and with very limited ability to tell you how
they actually did it (ask a professional pitcher how they pitch). A novice
on the other hand lacks automaticity, performance involves considerable
cognitive involvement and they can tell you exactly what they are trying to
do. This is the reason you recruit naive users for usability testing instead
of the programmer who cut the code and can walk through an application
effortlessly. Its not the skill that you're diferentiating its the level of
expertise.

You can therefore develop a user profile based on a definition of the
skills, rules or knowledge that your generic user requires. Finding out
about expertise requires that you know something about how much practice or
exposure a user has to the area of interest.

Anne Miller
Coordinator
Human Factors Online
Key Centre for Human Factors
University of Queensland
http://www.humanfactors.uq.edu.au