Usability Testing or Usability Engineering
Understanding Usability Engineering:
Usability Engineering is an empirical science and has quite a simple definition. It studies the human interaction and cognitive behavior of an individual with respect to performing a task. It could be as simple as a driving a vehicle or using a product. Users interaction in performing a task should be in synchronization with the workflow of the product. Usability Engineering as a science helps in achieving this goal.
Usability for a Product: A Product should be usable. It means that people can use a product easily and efficiently to accomplish their own tasks. A product, which is usable, enables workers to concentrate on their tasks and to do real work, rather than on the tools they use to perform their tasks.
Attributes of a usable product are:
� It’s easy to learn
� Efficient to use
� Provides quick recovery from errors
� Easy to remember
� Enjoyable to use
� Visually pleasing
Usability applies to every aspect of a product with which a person interacts (hardware, software, menus, icons, messages, documentation, training, and on-line help). Every design and development decision made throughout the product cycle has an impact on that product�s usability.
As customers depend more and more on software to get their jobs done and become more critical consumers, usability can be the critical factor that ensures that products will be used.
Usability testing is a technique used to evaluate a product by testing it on users. This can be seen as an irreplaceable usability practice, since it gives direct input on how real users use the system. This is in contrast with usability inspection methods where experts use different methods to evaluate a user interface without involving users.
Usability testing focuses on measuring a human-made product’s capacity to meet its intended purpose. Examples of products that commonly benefit from usability testing are web sites or web applications, computer interfaces, documents, or devices. Usability testing measures the usability, or ease of use, of a specific object or set of objects, whereas general human-computer interaction studies attempt to formulate universal principles.
Goals of Usability Testing:
During usability testing, the aim is to observe people using the product to discover errors and areas of improvement. Usability testing generally involves measuring how well test subjects respond in four areas: efficiency, accuracy, recall, and emotional response. The results of the first test can be treated as a baseline or control measurement; all subsequent tests can then be compared to the baseline to indicate improvement.
Efficiency – How long does it take people to complete basic tasks? (For example, find something to buy, create a new account, and order the item.)
Accuracy – How many mistakes did people make? (And were they fatal or recoverable with the right information?)
Recall – How much does the person remember afterwards or after periods of non-use?
Emotional response – How does the person feel about the tasks completed? Is the person confident, stressed? Would the user recommend this system to a friend?
Methods of Usability Testing:
1. User and task observations � observing users at their jobs, identifying their typical work tasks and procedures, analyzing their work processes, and understanding people in the context of their work.
2. Interviews, focus groups and questionnaires � meeting with users, finding out about their preferences, experiences and needs.
3. Benchmarking and competitive analysis � evaluating the usability of similar products in the marketplace.
4. Participatory design – participating in design and bringing the user�s perspective to the early stages of development.
5. Paper prototyping � including users early in the development process through prototypes prepared on paper before coding begins.
6. Creation of guidelines – helping to assure consistency in design through development of standards and guidelines.
7. Heuristic evaluations – evaluating software against accepted usability principles and making recommendations to enhance usability.
8. Usability testing – observing users performing real tasks with the application, recording what they do, analyzing the results and recommending appropriate changes.
Usability engineering provides important benefits in terms of cost, product quality and customer satisfaction. It can improve development productivity through more efficient design and fewer code revisions. It can help to eliminate over-design by emphasizing the functionality required to meet the needs of real users. Design problems can be detected earlier in the development process, saving both time and money. It can provide further cost savings through reduced support costs, reduced training requirements and greater user productivity. A usable product means more satisfied customers and a better reputation for the product and for the organization that developed it.
Today many leading corporations are incorporating usability engineering into their product development cycles. For them, usability is becoming a competitive advantage.
A usability test consists of following five characteristics:
- Each test has specific goals and concerns that are tested.
- The participants represent real users (6 to 12 participants are typical).
- The participants do real tasks.
- The participants are observed and recorded.
- The data is analyzed, problems diagnosed and recommendations made.
A usability test consists of following activities:
1. Planning the test, developing participant�s profiles, identifying participants from user pool, creating test materials, writing task scenarios and determining usability criteria and measures.
2. Preparing the test location, pilot testing materials and procedures.
3. Introducing the participant to the situation, the product and the procedure.
4. Running of the task-based test, where participants are asked to complete a series of tasks that address the specific goals and concerns being tested.
5. Participants are asked to “think aloud” (articulate their thoughts, feeling and actions). This data and the recorded video images, helps target areas that are confusing, unclear or misleading during the analysis stage.
6. Debriefing the participant to get final thoughts, subjective feelings about the product and suggestions for improvement.
7. Analyzing the data, making recommendations and documenting findings.
8. The deliverable from a usability test is a report that details the problems encountered by the participants and recommendations for chance based on known human factors, cognitive and behavioral principles and recognized best practices.