In large part, what makes something usable is the absence of frustration in using it. As we lay out the process and method for conducting usability testing in this book, we will rely on this definition of ‘‘usability;’’ when a product or service is truly usable, the user can do what he or she wants to do the way he or she expects to be able to do it, without hindrance, hesitation, or questions. (p.4)
To be usable, a product or service should be useful, efficient, effective, satisfying, learnable, and accessible. (p.4)
Most usability professionals spend most of their time working on eliminating design problems, trying to minimize frustration for users. This is a laudable goal! But know that it is a difficult one to attain for every user of your product. And it affects only a small part of the user’s experience of accomplishing a goal. (p.6)
Five Reasons Why Products Are Hard to Use (p.6)
1. Development focuses on the machine or system.
2. Target audiences change and adapt.
3. Designing usable products is difficult.
4. Team specialists don’t always work in integrated ways.
5. Design and implementation don’t always match.
The International Organization for Standardization (ISO) in standard 13407 says that UCD is ‘‘characterized by: the active involvement of users and a clear understanding of user and task requirements; an appropriate allocation of function between users and technology; the iteration of design solutions; multidisciplinary design.’’ (p.13)
(Usability Test)The intent is to ensure the creation of products that: (p.22)
1.Are useful to and valued by the target audience
2.Are easy to learn
3.Help people be effective and efficient at what they want to do Are satisfying (and possibly even delightful) to use
An important aspect of surveys is that their language must be crystal clear and understood in the same way by all readers, a task impossible to perform without multiple tested iterations and adequate preparation time. Again, asking people about what they do or have done is no substitute for observing them do it in a usability test. (p.18)
Usability testing is most powerful and most effective when implemented as part of an iterative product development process. That is, a cycle of design, test and measure, and redesign throughout the product development lifecycle has the greatest probability of concluding with a usable product. Even if important product flaws or deficiencies are missed during one test, another testing cycle offers the opportunity to identify these problems or issues. （p.28）
We feel very strongly that such an approach provides the value when resources are limited, and that one will obtain the best results by conducting a series of short, precise tests that build one upon the other. （p.28）
Exploratory or Formative Study (p.30)
Some typical user-oriented questions that an exploratory study would attempt to answer might include the following:
What do users conceive and think about using the product?
Does the product’s basic functionality have value to the user?
How easily and successfully can users navigate?
How easily do users make inferences about how to use this user inter- face, based on their previous experience?
What type of prerequisite information does a person need to use the product?
Which functions of the product are ‘‘walk up and use’’ and which will probably require either help or written documentation?
How should the table of contents be organized to accommodate both novice and experienced users?
Assessment or Summative Test (p.35)
The user will always perform tasks rather than simply walking through and commenting upon screens, pages, and so on.
The test moderator will lessen his or her interaction with the participant because there is less emphasis on thought processes and more on actual behaviors.
Quantitative measures will be collected
Verification or Validation Test (p.36)
It only makes sense then that the validation test itself can be used to initiate standards within the company for future products. Verification can accomplish the same thing. For example, if one establishes that a setup procedure for a software package works well and can be conducted within 5 minutes with no more than one error, it is important that future releases of the product perform to that standard or better. Products can then be designed with this benchmark as a target, so that usability does not degrade as more functions are added to future releases.
Still another objective of the validation test, or really any test conducted very late in the development cycle, has become known in the trade as ‘‘disaster or catastrophe insurance.’’ At this late stage, management is most concerned with the risk of placing into the marketplace a new product that contains major flaws or that might require recall. If such a flaw is discovered, slipping the schedule may be preferable to recalling the product or having to send out ‘‘fixes’’ to every user.
Because you are measuring user performance against a standard, you also need to determine beforehand how adherence to the standard will be measured, and what actions will be taken if the product does not meet its standards. (p.37)