Usability Techniques

1
Usability Techniques

• Lecture 13

2
Methods

• There are a variety of approaches to usability
  evaluation that you may choose to take. The
  methodologies can be divided into two broad
  categories those that gather data from actual
  users and those that can be applied without
  actual users present.
• Your choice of method depends on
• Cost of evaluation
• Appropriateness to project
• Time constraints
• Cost of implementation
• Cost of training new users

3
Risk

• Usability evaluations can be conducted at many
  stages during and after the design and
  development process. In choosing a method, it is
  important to calculate the cost not only in terms
  of time and materials involved, but also in terms
  of the impact on the end-users, especially
  considering the cost of losing return visitors to
  your website due to unusable design.

4
Cognitive Walkthrough Method

• Cognitive walkthroughs are performed at any stage
  of design using a prototype, a conceptual design
  document, or the final product. This is a more
  specific version of a design walkthrough,
  focusing on cognitive principles.
• Based on a user's goals, a group of evaluators
  steps through tasks, evaluating at each step how
  difficult it is for the user to identify and
  operate the interface element most relevant to
  their current subgoal and how clearly the system
  provides feedback to that action. Cognitive
  walkthroughs take into consideration the user's
  thought processes that contribute to decision
  making, such as memory load and ability to
  reason.

5
Focus Groups

• This is a data collecting technique where about 6
  to 9 users are brought together to discuss issues
  relating to the system. A human factors engineer
  plays the role of a moderator, who needs to
  prepare the list of issues to be discussed
  beforehand and seek to gather the needed
  information from the discussion. This can capture
  spontaneous user reactions and ideas that evolve
  in the dynamic group process.
• Focus groups are also good at discovering how the
  system being tested differs from the user's
  current expectations. As we see it, focus groups
  provide two major benefits. First, they are less
  expensive than conducting interviews with the
  same number of people. Second, they rely on group
  interaction to trigger memories that may not come
  up during interviews.

6
Prototyping

• Prototyping techniques involve developing
  representations of a target system for evaluation
  and testing purposes.
• Prototyping is an essential element of an
  iterative design approach, where designs are
  created, evaluated, and refined with the results
  of testing at each cycle feeding into the design
  focus of the next cycle.
• Prototypes can range from extremely simple
  sketches (low-fidelity prototypes) to full
  systems that contain nearly all the functionality
  of the final system (high-fidelity prototypes).

7
Task Analysis

• Task analysis is a method that evaluates how
  people actually accomplish things with software.
  Through observation and interviews with users, an
  analyst determines a set of goals belonging to
  the target user. Then, a set of tasks that
  support these goals is determined. These are
  prioritized based on criteria such as the
  importance of the goal to the organization and
  the frequency of task performance.
• The highest priority tasks are decomposed into
  their individual steps. The level of
  decomposition varies with the budget and type of
  system evaluated. The analyst then suggests ways
  to make the task more efficient or suggests new
  tasks which more effectively support the goals.
  It is important to recognize that the analysis is
  done from the perspective of the end-usernot
  from the point of view of managers or executives
  who do not necessarily use the system.

8
Usability Inspection / Heuristic Evaluation

• A usability inspection is a review of a system
  based on a set of guidelines. The review is
  conducted by a group of experts who are deeply
  familiar with the concepts of usability in
  design. The experts focus on a list of areas in
  design that have been shown to be troublesome for
  users.
• Usability guidelines are usually derived from
  studies in human-computer interaction,
  ergonomics, graphic design, information design,
  and cognitive psychology. Some areas that get
  evaluated are the language used in the system,
  the amount of recall required of the user at each
  step in a process, and how the system provides
  feedback to the user. In particular, issues such
  as clarity, consistency, navigation, and error
  minimization are analyzed. Once the problems are
  discovered, the experts make recommendations for
  resolving these issues.