Information Technology Reference
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is typically done by measuring the number of actions or steps that users took
in performing each task. An action can take many forms, such as clicking a link
on a web page, pressing a button on a microwave oven or a mobile phone, or
flipping a switch on an aircraft. Each action a user performs represents a certain
amount of effort. The more actions taken by a user, the more effort involved. In
most products, the goal is to increase productivity by minimizing the number
of discrete actions required to complete a task, thereby minimizing the amount
of effort.
What do we mean by effort? There are at least two types of effort: cognitive
and physical. Cognitive effort involves finding the right place to perform an
action (e.g., finding a link on a web page), deciding what action is necessary
(should I click this link?), and interpreting the results of the action. Physical
effort involves the physical activity required to take action, such as moving a
mouse, inputting text on a keyboard, turning on a switch, and many others.
AN INTERESTING WAY OF MEASURING COGNITIVE EFFORT
One way of measuring cognitive effort is using performance on a task that's peripheral,
or secondary, to the participants' primary task. The more cognitive effort the primary
task requires, the worse the performance on the secondary task will be. An interesting
variation of this was used by Ira Hyman and associates at Western Washington University
to measure cell phone distraction (Hyman et al., 2010). They had one of their students
ride a unicycle around a popular square on campus while wearing a clown suit (a rather
memorable sight!). Then they observed 347 pedestrians walking across the square, some
of whom were talking on their cell phones. After crossing the square, they asked the
pedestrians if they had seen a unicycling clown. The clown was remembered by 71% of
those walking with a friend, 61% of those listening to music, and 51% of those walking
alone. But only 25% of those talking on a cell phone remembered the unicycling clown!
Efficiency metrics work well if you are concerned not only with the time it takes
to complete a task but also the amount of cognitive and physical effort involved.
For example, if you're designing an automobile navigation system, you need to
make sure that it does not take much effort to interpret its navigation directions,
as the driver's attention must be focused on the road. It would be important to
minimize both physical and cognitive effort to use the navigation system.
4.4.1 Collecting and Measuring Efficiency
There are some important points to keep in mind when collecting and measur-
ing efficiency.
•
Identify the action(s) to be measured:
For websites, mouse clicks or page
views are common actions. For software, it might be mouse clicks or
keystrokes. For appliances or consumer electronics, it could be button
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