Planning - Measuring the User Experience: Collecting, Analyzing, and Presenting Usability Metrics - page 44

3.2 USER GOALS
When planning a usability study, you need to understand the users and what
they are trying to accomplish. For example, are users required to use the product
every day as part of their job? Are they likely to use the product only once or just
a few times? Are they using it frequently as a source of entertainment? It's critical
tounderstandwhatmatterstotheuser.Doestheusersimplywanttocomplete
ataskorisitsefficiencytheprimarydriver?Douserscareatallaboutthedesign
aesthetics of the product? All these questions boil down to measuring two main
aspects of the user experience: performance and satisfaction.
3.2.1 Performance
Performance is all about what the user actually does in interacting with the
product. It includes measuring the degree to which users can accomplish a task
or set of tasks successfully. Many measures related to the performance of these
tasks are also important, including the time it takes to perform each task, the
amount of effort to perform each (such as number of mouse clicks or amount
of cognitive effort), the number of errors committed, and the amount of time it
takes to become proficient in performing the tasks (learnability). Performance
measures are critical for many different types of products and applications, espe-
cially those where the user doesn't really have much choice in how they are used
(such as a company's internal applications). If users can't perform key tasks suc-
cessfully when using a product, it's likely to fail. Chapter 4 reviews different
types of performance measures.
3.2.2 Satisfaction
Satisfaction is all about what the user says or thinks about his interaction with
the product. The user might report that it was easy to use, that it was confusing,
or that it exceeded his expectations. The user might have opinions about the
product being visually appealing or untrustworthy. User satisfaction has many
different aspects. Satisfaction, and many other self-reported metrics, is impor-
tant for products where the user has some choice in their usage. This would cer-
tainly be true for most websites, software applications, and consumer products.
Satisfaction metrics are reviewed in Chapter 6.
DO PERFORMANCE AND SATISFACTION ALWAYS
CORRELATE?
Perhaps surprisingly, performance and satisfaction don't always go hand-in-hand.
We've seen many instances of a user struggling to perform key tasks with an application
and then giving it glowing satisfaction ratings. Conversely, we've seen users give poor
satisfaction ratings to an application that worked perfectly. So it's important that you
look at both performance and satisfaction metrics to get an accurate overall picture of